When I returned from US with my fresh PPL was told I needed the following:
As the PPL is only 35hrs out there I needed Dual Instruction to bring me up to 45HRS and familiarise me with the area and UK ATC procedures. This was probably a sales pitch rather anything else but was useful anyway.
UK Radio licence
UK medical AND valid FAA medical
Pass JAR law exam.
Maintain valid SFAR 73 if flying Robbies
Maintain valid FAR 61.56 bi-annual flight review, which might actually be annual if you have less than 100hrs. I think.
This then allowed me to fly Day VFR within the UK - nb not France etc.
The FAA PPL permits night flying, terrifyingly enough and this privelege can not be used in UK.
Sounds like aggro but at least you don't have to muck around with type ratings and have an excuse to go back to sunny states every so often.
CHeers.