The directors present their annual report and financial statements for the year ended 31 March 2025.

The principal activity of the company continued to be that of the manufacture of dosimeters for use in radiation quality control systems.

The results for the year are set out on page 6.

Ordinary dividends were paid amounting to £2,800,000. The directors do not recommend payment of a final dividend.

The directors who held office during the year and up to the date of signature of the financial statements were as follows:

The auditors, WSM Advisors Limited, have been reappointed in accordance with section 485 of the Companies Act 2006.

So far as each person who was a director at the date of approving this report is aware, there is no relevant audit information of which the company’s auditor is unaware. Additionally, the directors individually have taken all the necessary steps that they ought to have taken as directors in order to make themselves aware of all relevant audit information and to establish that the company’s auditor is aware of that information.

This report has been prepared in accordance with the provisions applicable to companies entitled to the medium-sized companies exemption.

The directors are responsible for preparing the annual report and the financial statements in accordance with applicable law and regulations.

Company law requires the directors to prepare financial statements for each financial year. Under that law the directors have elected to prepare the financial statements in accordance with United Kingdom Generally Accepted Accounting Practice (United Kingdom Accounting Standards and applicable law). Under company law, the directors must not approve the financial statements unless they are satisfied that they give a true and fair view of the state of affairs of the company and of the profit or loss of the company for that period.

In preparing these financial statements, the directors are required to:

• select suitable accounting policies and then apply them consistently;

• make judgements and accounting estimates that are reasonable and prudent; and

• prepare the financial statements on the going concern basis unless it is inappropriate to presume that the company will continue in business.

The directors are responsible for keeping adequate accounting records that are sufficient to show and explain the company’s transactions and disclose with reasonable accuracy at any time the financial position of the company and enable them to ensure that the financial statements comply with the Companies Act 2006. They are also responsible for safeguarding the assets of the company and hence for taking reasonable steps for the prevention and detection of fraud and other irregularities.

We have audited the financial statements of Harwell Dosimeters Limited (the 'company') for the year ended 31 March 2025 which comprise the statement of comprehensive income, the statement of financial position, the statement of changes in equity and notes to the financial statements, including significant accounting policies. The financial reporting framework that has been applied in their preparation is applicable law and United Kingdom Accounting Standards, including Financial Reporting Standard 102 The Financial Reporting Standard applicable in the UK and Republic of Ireland (United Kingdom Generally Accepted Accounting Practice).

In our opinion the financial statements:

• give a true and fair view of the state of the company's affairs as at 31 March 2025 and of its profit for the year then ended;

• have been properly prepared in accordance with United Kingdom Generally Accepted Accounting Practice; and

• have been prepared in accordance with the requirements of the Companies Act 2006.

Basis for opinion

We conducted our audit in accordance with International Standards on Auditing (UK) (ISAs (UK)) and applicable law. Our responsibilities under those standards are further described in the Auditor's responsibilities for the audit of the financial statements section of our report. We are independent of the company in accordance with the ethical requirements that are relevant to our audit of the financial statements in the UK, including the FRC’s Ethical Standard, and we have fulfilled our other ethical responsibilities in accordance with these requirements. We believe that the audit evidence we have obtained is sufficient and appropriate to provide a basis for our opinion.

Conclusions relating to going concern

In auditing the financial statements, we have concluded that the directors' use of the going concern basis of accounting in the preparation of the financial statements is appropriate.

Based on the work we have performed, we have not identified any material uncertainties relating to events or conditions that, individually or collectively, may cast significant doubt on the company's ability to continue as a going concern for a period of at least twelve months from when the financial statements are authorised for issue.

Our responsibilities and the responsibilities of the directors with respect to going concern are described in the relevant sections of this report.

Other information

The other information comprises the information included in the annual report other than the financial statements and our auditor's report thereon. The directors are responsible for the other information contained within the annual report. Our opinion on the financial statements does not cover the other information and, except to the extent otherwise explicitly stated in our report, we do not express any form of assurance conclusion thereon. Our responsibility is to read the other information and, in doing so, consider whether the other information is materially inconsistent with the financial statements or our knowledge obtained in the course of the audit, or otherwise appears to be materially misstated. If we identify such material inconsistencies or apparent material misstatements, we are required to determine whether this gives rise to a material misstatement in the financial statements themselves. If, based on the work we have performed, we conclude that there is a material misstatement of this other information, we are required to report that fact.

We have nothing to report in this regard.

Opinions on other matters prescribed by the Companies Act 2006

In our opinion, based on the work undertaken in the course of our audit:

• the information given in the directors' report for the financial year for which the financial statements are prepared is consistent with the financial statements; and

• the directors' report has been prepared in accordance with applicable legal requirements.

In the light of the knowledge and understanding of the company and its environment obtained in the course of the audit, we have not identified material misstatements in the directors' report. We have nothing to report in respect of the following matters in relation to which the Companies Act 2006 requires us to report to you if, in our opinion:

• adequate accounting records have not been kept, or returns adequate for our audit have not been received from branches not visited by us; or

• the financial statements are not in agreement with the accounting records and returns; or

• certain disclosures of remuneration specified by law are not made; or

• we have not received all the information and explanations we require for our audit; or

• the directors were not entitled to take advantage of the small companies exemption from the requirement to prepare a strategic report.

As explained more fully in the directors' responsibilities statement, the directors are responsible for the preparation of the financial statements and for being satisfied that they give a true and fair view, and for such internal control as the directors determine is necessary to enable the preparation of financial statements that are free from material misstatement, whether due to fraud or error. In preparing the financial statements, the directors are responsible for assessing the company's ability to continue as a going concern, disclosing, as applicable, matters related to going concern and using the going concern basis of accounting unless the directors either intend to liquidate the company or to cease operations, or have no realistic alternative but to do so.

Our objectives are to obtain reasonable assurance about whether the financial statements as a whole are free from material misstatement, whether due to fraud or error, and to issue an auditor’s report that includes our opinion. Reasonable assurance is a high level of assurance, but is not a guarantee that an audit conducted in accordance with ISAs (UK) will always detect a material misstatement when it exists. Misstatements can arise from fraud or error and are considered material if, individually or in the aggregate, they could reasonably be expected to influence the economic decisions of users taken on the basis of these financial statements.

Irregularities, including fraud, are instances of non-compliance with laws and regulations. We design procedures in line with our responsibilities, outlined above, to detect material misstatements in respect of irregularities, including fraud.

We evaluated management's incentives and opportunities for fraudulent manipulation of the financial statements (including the risk of override of controls) and determined that the principal risks were related to management bias in accounting estimates, manipulation of intra-group trading and posting inappropriate journal entries to manipulate the value of the company's assets.

Our approach to identifying and assessing the risks of material misstatement in respect of irregularities, including fraud and non-compliance with laws and regulations, was as follows:

• the senior statutory auditor ensured that the engagement team collectively had the appropriate competence, capabilities and skills to identify or recognise non-compliance with applicable laws and regulations;

• we identified the laws and regulations applicable to the company through discussions with directors and other management, and from our commercial knowledge and experience of the industry;

• we focused on specific laws and regulations which we considered may have a direct material effect on the financial statements or the operations of the company, including the Companies Act 2006 and taxation legislation;

• we assessed the extent of compliance with the laws and regulations identified above through making enquiries of management and inspecting legal correspondence; and

• identified laws and regulations were communicated within the audit team regularly and the team remained alert to instances of non-compliance throughout the audit.

To address the risk of fraud through management bias and override of controls, we:

• performed analytical procedures to identify any unusual or unexpected relationships;

• tested journal entries to identify unusual transactions;

• assessed whether judgements and assumptions made in determining the accounting estimates set out in Note 2 were indicative of potential bias; and

• investigated the rationale behind significant or unusual transactions.

In response to the risk of irregularities and non-compliance with laws and regulations, we designed procedures which included, but were not limited to:

• agreeing financial statement disclosures to underlying supporting documentation;

• reading the minutes of meetings of those charged with governance;

• enquiring of management as to actual and potential litigation and claims; and

• reviewing correspondence with HM Revenue and Customs, relevant regulators and the company’s legal advisors.

There are inherent limitations in our audit procedures described above. The more removed that laws and regulations are from financial transactions, the less likely it is that we would become aware of non-compliance. Auditing standards also limit the audit procedures required to identify non-compliance with laws and regulations to enquiry of the directors and other management and the inspection of regulatory and legal correspondence, if any.

Material misstatements that arise due to fraud can be harder to detect than those that arise from error as they may involve deliberate concealment or collusion.

A further description of our responsibilities is available on the Financial Reporting Council’s website at: https://www.frc.org.uk/auditorsresponsibilities. This description forms part of our auditor's report.

Use of our report

This report is made solely to the company's member in accordance with Chapter 3 of Part 16 of the Companies Act 2006. Our audit work has been undertaken so that we might state to the company's member those matters we are required to state to the member in an auditor's report and for no other purpose. To the fullest extent permitted by law, we do not accept or assume responsibility to anyone other than the company and the company's member, for our audit work, for this report, or for the opinions we have formed.

The income statement has been prepared on the basis that all operations are continuing operations.

These financial statements have been prepared in accordance with the provisions relating to medium-sized companies.

Harwell Dosimeters Limited is a private company limited by shares incorporated in England and Wales. The registered office is 2200 Renaissance, Basing View, Basingstoke, Hampshire, RG21 4EQ.

These financial statements have been prepared in accordance with FRS 102 “The Financial Reporting Standard applicable in the UK and Republic of Ireland” (“FRS 102”) and the requirements of the Companies Act 2006.

The financial statements are prepared in sterling, which is the functional currency of the company. Monetary amounts in these financial statements are rounded to the nearest £.

The financial statements have been prepared under the historical cost convention. The principal accounting policies adopted are set out below.

This company is a qualifying entity for the purposes of FRS 102, being a member of a group where the parent of that group prepares publicly available consolidated financial statements, including this company, which are intended to give a true and fair view of the assets, liabilities, financial position and profit or loss of the group. The company has therefore taken advantage of exemptions from the following disclosure requirements:

Section 7 ‘Statement of Cash Flows’: Presentation of a statement of cash flow and related notes and disclosures;

Section 11 ‘Basic Financial Instruments’ and Section 12 ‘Other Financial Instrument Issues’: Interest income/expense and net gains/losses for each category of financial instrument; basis of determining fair values; details of collateral, loan defaults or breaches, details of hedges, hedging fair value changes recognised in profit or loss and in other comprehensive income;

Section 26 ‘Share based Payment’: Share-based payment expense charged to profit or loss, reconciliation of opening and closing number and weighted average exercise price of share options, how the fair value of options granted was measured, measurement and carrying amount of liabilities for cash-settled share-based payments, explanation of modifications to arrangements;

Section 33 ‘Related Party Disclosures’: Compensation for key management personnel and transactions with wholly owned group companies.

The financial statements of the company are consolidated in the financial statements of STERIS plc. These consolidated financial statements are available from 70 Sir John Rogerson's Quay, Dublin 2, DO2 R296, Ireland.

For the year to 31 March 2025 the company made a profit amounting to £true2,460,602 and had net assets of £3,476,715. Although the company is expected to be profitable, the company has also received confirmation from its intermediate parent undertaking, STERIS Limited, of its intention to provide support, where needed, for a period of at least 12 months from the date of approval of the accounts. The directors therefore have a reasonable expectation that the company has adequate resources to continue in operational existence for the foreseeable future. Accordingly, the directors continue to adopt the going concern basis of accounting in preparing the financial statements.

Revenue is recognised at the fair value of the consideration received or receivable for goods and services provided in the normal course of business, and is shown net of VAT and other sales related taxes. The fair value of consideration takes into account trade discounts, settlement discounts and volume rebates.

Revenue from the sale of goods is recognised when the significant risks and rewards of ownership of the goods have passed to the buyer (usually on dispatch of the goods), the amount of revenue can be measured reliably, it is probable that the economic benefits associated with the transaction will flow to the entity and the costs incurred or to be incurred in respect of the transaction can be measured reliably.

Research expenditure is written off against profits in the year in which it is incurred. Identifiable development expenditure is capitalised to the extent that the technical, commercial and financial feasibility can be demonstrated.

Intellectual property rights, patents and know-how are amortised over a period of 10-25 years, being the directors estimate of their useful economic life. The director considers it appropriate to amortise the intellectual property right over 25 years due to the market in which the company is operating and its market share. The directors carry out an annual impairment review.

Property, plant and equipment are initially measured at cost and subsequently measured at cost or valuation, net of depreciation and any impairment losses.

Depreciation is recognised so as to write off the cost or valuation of assets less their residual values over their useful lives on the following bases:

The gain or loss arising on the disposal of an asset is determined as the difference between the sale proceeds and the carrying value of the asset, and is credited or charged to profit or loss.

At each reporting period end date, the company reviews the carrying amounts of its tangible and intangible assets to determine whether there is any indication that those assets have suffered an impairment loss. If any such indication exists, the recoverable amount of the asset is estimated in order to determine the extent of the impairment loss (if any). Where it is not possible to estimate the recoverable amount of an individual asset, the company estimates the recoverable amount of the cash-generating unit to which the asset belongs.

Recoverable amount is the higher of fair value less costs to sell and value in use. In assessing value in use, the estimated future cash flows are discounted to their present value using a pre-tax discount rate that reflects current market assessments of the time value of money and the risks specific to the asset for which the estimates of future cash flows have not been adjusted.

If the recoverable amount of an asset (or cash-generating unit) is estimated to be less than its carrying amount, the carrying amount of the asset (or cash-generating unit) is reduced to its recoverable amount. An impairment loss is recognised immediately in profit or loss.

Recognised impairment losses are reversed if, and only if, the reasons for the impairment loss have ceased to apply. Where an impairment loss subsequently reverses, the carrying amount of the asset (or cash-generating unit) is increased to the revised estimate of its recoverable amount, but so that the increased carrying amount does not exceed the carrying amount that would have been determined had no impairment loss been recognised for the asset (or cash-generating unit) in prior years. A reversal of an impairment loss is recognised immediately in profit or loss.

Inventories are stated at the lower of cost and estimated selling price less costs to complete and sell. Cost comprises direct materials and, where applicable, direct labour costs and those overheads that have been incurred in bringing the inventories to their present location and condition.

Inventories held for distribution at no or nominal consideration are measured at the lower of cost and replacement cost, adjusted where applicable for any loss of service potential.

At each reporting date, an assessment is made for impairment. Any excess of the carrying amount of inventories over its estimated selling price less costs to complete and sell is recognised as an impairment loss in profit or loss. Reversals of impairment losses are also recognised in profit or loss.

Cash and cash equivalents are basic financial assets and include cash in hand and deposits held at call with banks.

The company has elected to apply the provisions of Section 11 ‘Basic Financial Instruments’ and Section 12 ‘Other Financial Instruments Issues’ of FRS 102 to all of its financial instruments.

Financial instruments are recognised in the company's statement of financial position when the company becomes party to the contractual provisions of the instrument.

Financial assets and liabilities are offset, with the net amounts presented in the financial statements, when there is a legally enforceable right to set off the recognised amounts and there is an intention to settle on a net basis or to realise the asset and settle the liability simultaneously.

Basic financial assets, which include trade and other receivables and cash and bank balances, are initially measured at transaction price including transaction costs and are subsequently carried at amortised cost using the effective interest method unless the arrangement constitutes a financing transaction, where the transaction is measured at the present value of the future receipts discounted at a market rate of interest. Financial assets classified as receivable within one year are not amortised.

Other financial assets, including investments in equity instruments which are not subsidiaries, associates or joint ventures, are initially measured at fair value, which is normally the transaction price. Such assets are subsequently carried at fair value and the changes in fair value are recognised in profit or loss, except that investments in equity instruments that are not publicly traded and whose fair values cannot be measured reliably are measured at cost less impairment.

Financial assets, other than those held at fair value through profit and loss, are assessed for indicators of impairment at each reporting end date.

Financial assets are impaired where there is objective evidence that, as a result of one or more events that occurred after the initial recognition of the financial asset, the estimated future cash flows have been affected. If an asset is impaired, the impairment loss is the difference between the carrying amount and the present value of the estimated cash flows discounted at the asset’s original effective interest rate. The impairment loss is recognised in profit or loss.

If there is a decrease in the impairment loss arising from an event occurring after the impairment was recognised, the impairment is reversed. The reversal is such that the current carrying amount does not exceed what the carrying amount would have been, had the impairment not previously been recognised. The impairment reversal is recognised in profit or loss.

Financial assets are derecognised only when the contractual rights to the cash flows from the asset expire or are settled, or when the company transfers the financial asset and substantially all the risks and rewards of ownership to another entity, or if some significant risks and rewards of ownership are retained but control of the asset has transferred to another party that is able to sell the asset in its entirety to an unrelated third party.

Financial liabilities and equity instruments are classified according to the substance of the contractual arrangements entered into. An equity instrument is any contract that evidences a residual interest in the assets of the company after deducting all of its liabilities.

Basic financial liabilities, including trade and other payables and loans from fellow group companies, are initially recognised at transaction price unless the arrangement constitutes a financing transaction, where the debt instrument is measured at the present value of the future payments discounted at a market rate of interest. Financial liabilities classified as payable within one year are not amortised.

Debt instruments are subsequently carried at amortised cost, using the effective interest rate method.

Trade payables are obligations to pay for goods or services that have been acquired in the ordinary course of business from suppliers. Amounts payable are classified as current liabilities if payment is due within one year or less. If not, they are presented as non-current liabilities. Trade payables are recognised initially at transaction price and subsequently measured at amortised cost using the effective interest method.

Derivatives, including interest rate swaps and forward foreign exchange contracts, are not basic financial instruments. Derivatives are initially recognised at fair value on the date a derivative contract is entered into and are subsequently re-measured at their fair value. Changes in the fair value of derivatives are recognised in profit or loss in finance costs or finance income as appropriate, unless hedge accounting is applied and the hedge is a cash flow hedge.

Debt instruments that do not meet the conditions in FRS 102 paragraph 11.9 are subsequently measured at fair value through profit or loss. Debt instruments may be designated as being measured at fair value through profit or loss to eliminate or reduce an accounting mismatch or if the instruments are measured and their performance evaluated on a fair value basis in accordance with a documented risk management or investment strategy.

Financial liabilities are derecognised when the company’s contractual obligations expire or are discharged or cancelled.

Equity instruments issued by the company are recorded at the proceeds received, net of transaction costs. Dividends payable on equity instruments are recognised as liabilities once they are no longer at the discretion of the company.

The tax expense represents the sum of the tax currently payable and deferred tax.

The tax currently payable is based on taxable profit for the year. Taxable profit differs from net profit as reported in the income statement because it excludes items of income or expense that are taxable or deductible in other years and it further excludes items that are never taxable or deductible. The company’s liability for current tax is calculated using tax rates that have been enacted or substantively enacted by the reporting end date.

Deferred tax liabilities are generally recognised for all timing differences and deferred tax assets are recognised to the extent that it is probable that they will be recovered against the reversal of deferred tax liabilities or other future taxable profits. Such assets and liabilities are not recognised if the timing difference arises from goodwill or from the initial recognition of other assets and liabilities in a transaction that affects neither the tax profit nor the accounting profit.

The carrying amount of deferred tax assets is reviewed at each reporting end date and reduced to the extent that it is no longer probable that sufficient taxable profits will be available to allow all or part of the asset to be recovered. Deferred tax is calculated at the tax rates that are expected to apply in the period when the liability is settled or the asset is realised. Deferred tax is charged or credited in the income statement, except when it relates to items charged or credited directly to equity, in which case the deferred tax is also dealt with in equity. Deferred tax assets and liabilities are offset when the company has a legally enforceable right to offset current tax assets and liabilities and the deferred tax assets and liabilities relate to taxes levied by the same tax authority.

The costs of short-term employee benefits are recognised as a liability and an expense, unless those costs are required to be recognised as part of the cost of stock or non-current assets.

The cost of any unused holiday entitlement is recognised in the period in which the employee’s services are received.

Payments to defined contribution retirement benefit schemes are charged as an expense as they fall due.

Rentals payable under operating leases, including any lease incentives received, are charged to profit or loss on a straight line basis over the term of the relevant lease except where another more systematic basis is more representative of the time pattern in which economic benefits from the leases asset are consumed.

Transactions in currencies other than pounds sterling are recorded at the rates of exchange prevailing at the dates of the transactions. At each reporting end date, monetary assets and liabilities that are denominated in foreign currencies are retranslated at the rates prevailing on the reporting end date. Gains and losses arising on translation in the period are included in profit or loss.

In the application of the company’s accounting policies, the directors are required to make judgements, estimates and assumptions about the carrying amount of assets and liabilities that are not readily apparent from other sources. The estimates and associated assumptions are based on historical experience and other factors that are considered to be relevant. Actual results may differ from these estimates.

The estimates and underlying assumptions are reviewed on an ongoing basis. Revisions to accounting estimates are recognised in the period in which the estimate is revised where the revision affects only that period, or in the period of the revision and future periods where the revision affects both current and future periods.

The following judgements (apart from those involving estimates) have had the most significant effect on amounts recognised in the financial statements.

Inventories are valued at the lower of cost and net realisable value. Net realisable value includes, where necessary, provisions for slow moving and obsolete stocks. Calculation of these provisions requires judgements to be made, which include forecast consumer demand, the promotional, competitive and economic environment and inventory loss trends.

The estimates and assumptions which have a significant risk of causing a material adjustment to the carrying amount of assets and liabilities are as follows.

The cost of defined benefit pension plans are determined using actuarial valuations. The actuarial valuation involves making assumptions about discount rates, inflation, future salary increases, mortality rates and future pension increases. Due to the complexity of the valuation, the underlying assumptions and the long-term nature of these plans, such estimates are subject to significant uncertainty. In relation to the company’s defined benefit pension scheme, actuarial assumptions are established using relevant market benchmark data and with the advice of external qualified actuaries. Pension valuations are most sensitive to changes in the underlying discount rate and inflation assumptions.

The average monthly number of persons (including directors) employed by the company during the year was:

Their aggregate remuneration comprised:

The actual charge for the year can be reconciled to the expected charge for the year based on the profit or loss and the standard rate of tax as follows:

In addition to the amount charged to the income statement, the following amounts relating to tax have been recognised directly in other comprehensive income:

Impairment tests have been carried out where appropriate and the following impairment losses have been recognised in profit or loss:

Deferred tax assets and liabilities are offset where the company has a legally enforceable right to do so. The following is the analysis of the deferred tax balances (after offset) for financial reporting purposes:

The deferred tax liability set out above is expected to reverse within 12 months and relates to accelerated capital allowances that are expected to mature within the same period.

The company operates a defined contribution pension scheme for all qualifying employees. The assets of the scheme are held separately from those of the company in an independently administered fund.

At the reporting end date the company had outstanding commitments for future minimum lease payments under non-cancellable operating leases, which fall due as follows:

Amounts contracted for but not provided in the financial statements:

The parent company of Harwell Dosimeters Limited is Synergy Health Holdings Limited. Its registered office is 2200 Renaissance, Basing View, Basingstoke, RG21 4EQ.

The ultimate parent undertaking and controlling party is STERIS plc, a company incorporated and domiciled in Ireland.

At 31 March 2025 the largest and smallest group in which the results of the company are consolidated is that of STERIS plc. The consolidated financial statements of the group are available to the public and may be obtained from 70 Sir John Rogerson's Quay, Dublin 2, DO2 R296, Ireland.