Just checked;-
Veterinary Requirements - from July 3rd 2004
An EU Pet Passport issued by your vet.
To obtain this, you must first have your pet microchipped by your vet. The vet must then vaccinate your pet against rabies.
If your pet is not going to be brought back to the UK your pet is now ready to go.
If you do intend to return to the UK then the vet must obtain a blood sample 30 days after the rabies vaccination and submit it for testing. Assuming that this result is positive, the details of the blood test will be entered into the Pet Passport.
Airlines require assurance that your pet is healthy enough to fly. Therefore your pet must be inspected by a vet shortly (preferably within a week) prior to the flight. The vet must then issue a fitness to fly (or private health) certificate.
I think I had to pay about £70 for the certs, I can't remember if that was for one or two. Although I think it was for two.