I searched online for the part number and ordered the tips from my usual VW dealer. One of my first buys there in 2009.
Many euros spent there since (with increasing discounts too).
I spent 85 £ but in the GT Sport, that picture is from my Ed. 30 with a BCS Powervalve turbo-back exhaust (much more expensive).
These are the pictures from my GT Sport. The tips are smaller, so I now advise bigger tips (90 mm):
They were very dirty tips here:
IMO they are a bit low at the moment, they were better aligned with my previous genuine GTI rear valance.