This subject is discussed under medical and health, The JAR regs are a lot more stringent that the more forward thinking Aussies and Americans where a practical test (as you have done) is acceptable.
In the EU if you fail the Ishihara tests (numbers in dots) you can take the Holmes-White lantern test (in the UK) which is just as tricky or similar tests in other EU countries.
There is no test looking at lights from an aircraft or the control tower meaning that some people who can get an FAA or Aussie class 1 medical cannot get a JAR class 1 but fly safely into LHR in a 747 under a N reg a/c
The situation is unfair, in Australia it was challenged in the courts by a doctor before the regs were changed but here they won't even consider a practical test.
Maybe someone should challenge it in the European court of human rights as the regs are not based on scientific research