I was told that the UK is already using jar for the medicals. About the regulations, you should find that in jar fcl part 3. You must know that they are still discuss several medical subjects and that some things can change. If you can do a national medical, try to do that. If you pass this one, you will get a waiver for the rest on your career when you do a jar medical according to jar fcl 3.005 b(1) en (4). You will get then a jar fcl medical with the restriction on it:'' for english registerd aircraft only''. Another option is to find out which Europian country still exams on national standerds and after you pass these, file a request with the caa for a national validation( for english registerd aircraft only)