You should just call the CAA and ask! I am assuming you haven't had any renewals sice 2002 or you'd already know, but if it is just like a normal annual renewal then it is nothing too interesting.....blood pressure, urine test, blood sample, reflexes etc. If you wear glasses / contacts, get a new prescription (on the CAA approved form only they won't accept anything your optician will give you) and take it with you. Possibly an audiogram and ECG depending on how old you are...I reckon after 5 years they will do most things again though....the CAA will advise. It is nothing like the initial though - you'll be in and out of the place in 15/20 minutes.