I had a problem with corrosion on mine, where the wing meets the sill. The corrosion was on the tops of the sill. VW said no from a picture...err i dont think so.
I rang VW customer care and said i want a paint accessor to come out and look, otherwise i would be taking it to other "paint experts" for there opinion.
They got back to me and agreed to carry the work out...you just gotta be firm but not over the top cos nobody likes that.
I had the same prob as Lyons though... although the paint work on mine was brilliant, shame it didnt last more than 2 weeks before peeling off. 5 times in total they had my car back. They blamed it on the primer and said they had to use a different make in the end.
I only took it back to the same VW bodyshop because they begged me to (the dealer).
Anyway, ring VW customer care and let them know pal, im sure they will sort it, just keep at them