Will you really need to convert the foreign licence? Any ICAO PPL is sufficient for enroling in the UK/EASA ATPL theoretical knowledge & CPL modular training courses.
Should you wish to obtain a UK Part-FCL PPL, you'll need,
inter alia, to either (1) have experience of 100 hours of flight time as a pilot
or (2) undergo whatever training that a UK training organisation deems necessary, before attempting the PPL skill test. In case (1) you'll only need to write two of the UK PPL theory exams but in case (2) all nine must be written. Routes 1 and 2 respectively are addressed at
https://www.caa.co.uk/general-aviati...-january-2023/
You may apply to UK CAA for a validation of the ICAO PPL. This would allow you to fly a UK-registered Part-21 aeroplane in a non-commercial operation for up to 28 days in the calendar year. The validation requires only acclimatisation training with a UK instructor and some UK CAA paperwork—no UK medical, no UK PPL exams, no UK PPL skill test. The validation is a useful option for reaching the 100 hours of experience needed under route 1 for a PPL conversion, should you really need one. Detail about the validation are in art 8(3) of Commission Delegated Regulation (EU) 2020/723, as retained and amended by the UK, available from UK CAA at
https://www.caa.co.uk/uk-regulations...gm-cs/aircrew/