Thanks for the advice. What options are available on the normal GTi that wouldn't be on an anniversary? There's a nice one on Autotrader but the guy isn't answering his phone. He also has no mention of his location 
if its a land line you can get the area from the area code
AFAIK the only options on the anniversaries were cruise, parking sensors and sat nav.
with the GT TDI 150 you could have all the options the anni had as well as xenons, leather / leather recaros, front arm rest, auto dimming rear view mirror, raintronic, winter pack, heated seats, and an extra 2 doors

the only things you couldn't have as a factory option are the anniversary bits like the rims, the body kit, the gear knob etc (all of this is available from places like vagparts.co.uk)
don't get me wrong the anniversary is a very nice car, just you'll get more more option wise for your money with a GT TDI 150 PD, and pretty much everything extra the anniversary had can be added aftermarket eg the S3 / VRS / TT / Leon etc brakes