Hi, I'm new here, but thought I'd add to this.
I picked up my 07 Edition 30 just over 2 weeks ago. It's a black one and black paint + dark wheel arch meant I couldn't see any rust on the wings during the viewing.
However, after getting the car home, I jacked up the offside, removed the arch liner and low and behold, the paint is just starting to bulge on the arch lip, directly below the foam. It's far from bad and I'd estimate it's 12-18 months away from spreading around to the front of the wings. No sign of rust at all on the nearside.
Wanting to catch it early, I took it to Inchcape VW in Colchester last week. My car is FSH, standard and factory paint thickness (around 130 microns). A few days later the car got booked into their body shop, no questions asked. No contribution required from me.
As the rusting is in it's very early stages, I've asked for a repair in preference to replacement because I don't want a paint mismatch. The VW guy said it's up to the body shop to decide that. If they can't guarantee the rust won't come back, they will replace the wing. If it comes to that, I will happily stump up for the blending. Whilst they're there and have the paint gun in their hand and all that.
Good luck people. If your car is original and accident free, there is no reason why you shouldn't get 100% contribution, but in the first instance, don't go in there with a defensive attitude, especially if the dealer you choose doesn't know you or your car. Play nice and you're more likely to get the result you're looking for