Off the CAA Micro site here:
https://info.caa.co.uk/uk-eu-transit...ercial-pilots/
Article 6 reads as follows:
For the validation of private pilot licences with an instrument rating, or Commercial Pilot Licences (‘CPL’) and Airline Transport Pilot Licences (‘ATPL’) with an instrument rating where the pilot intends only to exercise private pilot privileges, holders shall comply with all of the following requirements:
(a) complete the skill test for instrument rating and the type or class ratings relevant to the privileges of the licence held, in accordance with Appendix 7 and Appendix 9 of Annex I (Part-FCL) to Regulation (EU) No 1178/2011; 2.6.2020 EN Official Journal of the European Union L 170/3
(b) demonstrate knowledge of Air Law, Aeronautical Weather Codes, Flight Planning and Performance (IR) and Human Performance;
(c) demonstrate language proficiency in accordance with FCL.055 of Annex I (Part-FCL) to Regulation (EU) No 1178/2011;
(d) hold at least a valid Class 2 medical certificate issued in accordance with Annex 1 to the Chicago Convention;
(e) have a minimum experience of at least 100 hours of instrument flight time as pilot in command (‘PIC’) in the relevant category of aircraft.
So I take it you want to fly Privately not Commercial, you need to talk to an ATO, your local flying school will be able to help.