The actual rules are here and are unchanged: https://eurid.eu/media/filer_public/76/48/7648e621-0c5d-4c09-8bde-e5622cb6b23e/registration_policy_en.pdf
They were written by British civil servants working with their European conterparts.
They were approved by British politicians working with their European conterparts.
They were implemented by authority of the British Parliament.
SECTION 5. PROVIDING ACCURATE AND COMPLETE CONTACT INFORMATION
(ii) address and country within the European Union, Norway, Iceland or Liechtenstein
a. where the registered office, central administration or principal place of business of the undertaking of the Registrant is located or
b. where the organisation of the Registrant is established or
c. where the Registrant resides;
SECTION 12. PROCEDURE FOR THE REVOCATION OF DOMAIN NAMES
1. The Registry may revoke a Domain Name at its own discretion exclusively on the following grounds:
(i) outstanding unpaid debts owed by the Registrar to the Registry;
(ii) the Registrant’s not or no longer fulfilling the General Eligibility Criteria provided under Article 5(2)(b) of the .eu Regulation;
(iii) breach of the Rules by the Registrant.
Any domain registered with an address in the UK will by in breach of 5.(ii) at from the end of next month.