Revalidation
I add a little note.
The training flight for the purpose of revalidation must be undertaken with a JAA Instructor/CRI for it to be valid and cannot be less than 1 hour in duration and must also be undertaken during a single flight. The JAA Instructor/CRI then annotates your log book to the effect that you have satisfied the requirement. THIS FLIGHT DOSN'T AUTOMATICALLY REVALIDATE YOU!
You must, before your validaty expires, have your licence signed by a JAA Examiner. If you overun the revalidation date you will have lapsed and are grounded. You will then need to undertake a RENEWAL TEST with a JAA Examiner in a dual controlled aeroplane that holds a C of A (Private or Public). Public if you are not a 5%+ beneficial share holder. The test content is no more than the recommended content for the revalidation training flight. It is not a full Skill Test.
BEagle has made all the other points that you must bear in mind. Training cannot normally be undertaken in a PFA aeroplane but has been said, ask! Don't ask, don't get.