To renew your MEP/IR, it is training as required at an ATO plus a Proficiency Check. The training recommended under EASA is stated at Appendix 4 in CAA Standards Document 14(A). You are recommended for test by the ATO upon completion of training.
http://www.caa.co.uk/docs/33/Standar...Nov%202014.pdf
If you hold a FAA Private with ASEL/AMEL, all you need to do is a Flight Review with a FAA CFI to renew these privileges.