Visited my local locksmiths today who saw it as no problem to code a keyfob so it would lock/unlock, cut me a new keyblade and code a transponder.
They plugged in their diagnostic unit to the canbus but it could not extract the transponder pin number from the ECU. They suggested the reason was because it may have been remapped. I'm not so sure, but if so it seems a pity as he wanted £90 for the lot.
My next plan is for him to copy my key, do me a keyfob and supply a transponder. Then I just have to get VW to gently pull my trousers down in public whilst they code my transponder...