By the way the CAA in England have been letting FAA people fly BA/ATLAS 747's for yrs now (same deal)...so I think you know where you can put your flag of convenience
To the best of my knowledge the CAA insisted on the 14 exams being completed within a 12 month period.....BALPA also took a dim view on the practise..which contributed to the CAA's insistence.
Edited cos its more hassle than its worth