You will need to do a BFR to renew the FAA side of your licences, lots of people you can do that with in the UK, PM me if you want some suggestions.
To add MEP onto your FAA licence in the UK is significantly more difficult due to the requirement for an examiner (DPE) rather than an instructor.
Its worth looking at Return Home
To the best of my knowledge Tom Hughston is the only resident DPE in the UK.
You may find it cheaper to sort it when you are next in America.