In reply to Frank the Husky:
Any vet can do the worm thing - just google one. It can be done up to five days before leaving I think so you don't need to leave it to the last minute. They just give a tablet and sign the PP. Whenever we take our dog to the UK we get it done down here a few days before leaving.
My local vet (southern French Alps) is always doing it for British tourists this time of year.
I just checked the Calais tourist office website and they have a list of recommended vets (although they're not listed that I can find on the site). You can call them on +33 (0)321 96 62 40
Post edited at 11:12