Senior PLC — Major Shareholding Notification 2026

Mar 10, 2026

National Storage Mechanism | Additional information

Form 8.3

FORM 8.3

PUBLIC OPENING POSITION DISCLOSURE/DEALING DISCLOSURE BY

A PERSON WITH INTERESTS IN RELEVANT SECURITIES REPRESENTING 1% OR MORE

Rule 8.3 of the Takeover Code (the “Code”)

1. KEY INFORMATION

(a) Full name of discloser:	Computershare Trustees (Jersey) Limited as Trustee of Senior Plc Employee Benefit Trust
(b) Owner or controller of interests and short positions disclosed, if different from 1(a): The naming of nominee or vehicle companies is insufficient. For a trust, the trustee(s), settlor and beneficiaries must be named.	Trustee is Senior Plc Employee Benefit Trust Settlor is Senior plc Beneficiary is defined in the Trust Deed as 1. any Employee or ex-Employee of the Group; and 2. any individual who in relation to any person within (i) of this definition in his or her husband, wife, widow, or widower; or 3. any individual who in relation to any person within (i) of this definition is his or her child (or stepchild) under the age of 18. Employee is defined as in relation to any company includes a director (but not a non-executive director) and the expressions “employment” and “employed” shall be construed accordingly. Group means the Company, its Subsidiaries, and any company (together with Subsidiaries of such a company ) which controls (within the meaning of Section 840 of the Income and Corporation Taxes Act 1988) the Company for the time being and the expression “Group Company” shall be construed accordingly.
(c) Name of offeror/offeree in relation to whose relevant securities this form relates: Use a separate form for each offeror/offeree	Senior plc as Offeree
(d) If an exempt fund manager connected with an offeror/offeree, state this and specify identity of offeror/offeree:
(e) Date position held/dealing undertaken: For an opening position disclosure, state the latest practicable date prior to the disclosure	09 March 2026
(f) In addition to the company in 1(c) above, is the discloser making disclosures in respect of any other party to the offer? If it is a cash offer or possible cash offer, state “N/A”	N/A

2. POSITIONS OF THE PERSON MAKING THE DISCLOSURE

If there are positions or rights to subscribe to disclose in more than one class of relevant securities of the offeror or offeree named in 1(c), copy table 2(a) or (b) (as appropriate) for each additional class of relevant security.

(a) Interests and short positions in the relevant securities of the offeror or offeree to which the disclosure relates following the dealing (if any)

Class of relevant security:	Ordinary shares 10p
	Interests		Short positions
	Number	%	Number	%
(1) Relevant securities owned and/or controlled:	10,823,618	2.5806
(2) Cash-settled derivatives:
(3) Stock-settled derivatives (including options) and agreements to purchase/sell:
TOTAL:	10,823,618	2.5806

All interests and all short positions should be disclosed.

Details of any open stock-settled derivative positions (including traded options), or agreements to purchase or sell relevant securities, should be given on a Supplemental Form 8 (Open Positions).

(b) Rights to subscribe for new securities (including directors’ and other employee options)

Class of relevant security in relation to which subscription right exists:
Details, including nature of the rights concerned and relevant percentages:

3. DEALINGS (IF ANY) BY THE PERSON MAKING THE DISCLOSURE

Where there have been dealings in more than one class of relevant securities of the offeror or offeree named in 1(c), copy table 3(a), (b), (c) or (d) (as appropriate) for each additional class of relevant security dealt in.

The currency of all prices and other monetary amounts should be stated.

(a) Purchases and sales

Class of relevant security	Purchase/sale	Number of securities	Price per unit

(b) Cash-settled derivative transactions

Class of relevant security	Product description e.g. CFD	Nature of dealing e.g. opening/closing a long/short position, increasing/reducing a long/short position	Number of reference securities	Price per unit

(c) Stock-settled derivative transactions (including options)

(i) Writing, selling, purchasing or varying

Class of relevant security	Product description e.g. call option	Writing, purchasing, selling, varying etc.	Number of securities to which option relates	Exercise price per unit	Type e.g. American, European etc.	Expiry date	Option money paid/ received per unit

(ii) Exercise

Class of relevant security	Product description e.g. call option	Exercising/ exercised against	Number of securities	Exercise price per unit

(d) Other dealings (including subscribing for new securities)

Class of relevant security	Nature of dealing e.g. subscription, conversion	Details	Price per unit (if applicable)

4. OTHER INFORMATION

(a) Indemnity and other dealing arrangements

Details of any indemnity or option arrangement, or any agreement or understanding, formal or informal, relating to relevant securities which may be an inducement to deal or refrain from dealing entered into by the person making the disclosure and any party to the offer or any person acting in concert with a party to the offer: Irrevocable commitments and letters of intent should not be included. If there are no such agreements, arrangements or understandings, state “none”

(b) Agreements, arrangements or understandings relating to options or derivatives

Details of any agreement, arrangement or understanding, formal or informal, between the person making the disclosure and any other person relating to: (i) the voting rights of any relevant securities under any option; or (ii) the voting rights or future acquisition or disposal of any relevant securities to which any derivative is referenced: If there are no such agreements, arrangements or understandings, state “none”

(c) Attachments

Is a Supplemental Form 8 (Open Positions) attached?	NO

Date of disclosure:	10 March 2026
Contact name:	Ryan Gough
Telephone number*:	+4401534281829

Public disclosures under Rule 8 of the Code must be made to a Regulatory Information Service.

The Panel’s Market Surveillance Unit is available for consultation in relation to the Code’s disclosure requirements on +44 (0)20 7638 0129.

*If the discloser is a natural person, a telephone number does not need to be included, provided contact information has been provided to the Panel’s Market Surveillance Unit.

The Code can be viewed on the Panel’s website at www.thetakeoverpanel.org.uk.

JLM 10 March 2026

View source version on businesswire.com: https://www.businesswire.com/news/home/20260310315161/en/

Computershare Trustees (Jersey) Limited