If you get the CAA PPL revalidated first, then I could possibly do your BFR in England/Essex.
I'm not a JAA FI, or holding a JAA CPL (yet) so I don't know if it could be done. I am a current FAA CFI & I'd do it for free to save you having to go stateside if that is a loop hole we could use.
Ideally you'd need to find a dual rated JAA FI/FAA CFI.
The BFR consists of a min. 1 hour ground and a 1 hour flight.