Unless your rating was done under a JAR TRTO then I'm afraid it won't carry over to the JAR ATPL. A pity really. If you have 500 hours on it then you can "just" do an LST on it with the CAA observing the ride.
At the moment, a JAR TRTO will charge about ~20K GBP for an A320 rating. (No accom included).
Painful isn't it?