For what its worth, I ordered a pair of the eBay wings a few weeks back and got one of them fitted yesterday. They're ok - fitment around the bottom of the A pillar isn't quite as good as I'd hoped but going to take another look at it at a later date as I was running out of day light but the colour match is spot on and all other edges lined up as per the OEM wing.
Removing the original wing, you can really see what a total hash VW made of gluing that massive foam, water holding pad to the wing. What the hell was their thinking behind that!?
Anyway, one side of the car looks a little tidier now anyway - will get the other done ASAP.