Besides, you don't have to keep your FAA IR current f you for plan on flying a N-registered aircraft.
I really do not understand that sentence.... I think you missed something.
Also the two names that you quoted in the UK would be way too expensive for a FAA IPC. They are DPE's and will charge accordingly.
Take a look instead at a FAA CFII who can handle the IPC e.g. iflyfaa.com based at Norwich.