patlolo - I can't find any difference of opinion in the replies to your question, they all say substantially the same thing. If you get a JAR CPL issued on the basis of your UK CPL you will not carry over the theory credits for a JAR ATPL.
Your UK credits will remain valid for the issue of a UK ATPL (until the 2002 deadline) and indefinitely for the issue of the first multi-crew type rating on a JAR or UK CPL.
That is not opinion - it is fact. No matter how many times you ask the question, you will always get the same answer.
The reason is pretty obvious. If you want an ATPL, you need to pass the appropriate examinations or have sufficient, relevant experience. You wouldn't expect to get a UK ATPL issued on the basis of passing the FAA ATPL examinations, or vice versa, so why expect to get a JAA ATPL issued on the basis of the UK (or french, Spanish, Dutch, etc.)exams.