The usual scare stories from BB, without references as usual.
how do the CAA react if you take your FAA IR and your JAA IR exams (done at Gatwick) and just do the checkride in Swissland?
The CAA have no say in the matter; a JAA IR is a JAA IR.
The CAA are not delighted about so many ATPL candidates doing their initial colour vision test in Hungary, but they cannot do anything about it.
However the 15hrs is a bit moot because some local flying will be required anyway, just to get pointers on what the JAA IR examiner (whose habits will normally be known locally) will expect.