I have recently purchased the VW Roof Bars, and Cycle Carrier from Volkswagen. The roof bars are excellent, very easy to fit as it usually takes me less than 10 minutes for both and once on they are solid - worth the money. Like ajmoir36 I purchased mine from eBay (new), but for quite a bit more than £20!
The cycle carrier however I have found to be utter rubbish, and I paid full price for it (still trying to get rid of it now). With my bike loaded on it, and strapped down the best it could be and the support in the correct place the bike still wobbled and just didn't sit in the holder correctly. From speaking with other people who use the carrier on their cars, all opinions I have found to be the same - rubbish.
I couldn't recommend more that you get a Thule Proride 591 alongside the VW roof bars for carrying bike(s), to set up both and drive off I can usually do it in 20 minutes and the bike is very stable with the 591, much more than what the VW Cycle Carrier was.
Hope that helps.
