Yes this seems to be fairly common to Audi's and VW. I got the same prob with my '98 A4. The most sold bit at the the local eurocarparts is suspension links! Talking to a mate of mine who's got VW Passat, it is the lower ones that give up on them, also known as <veh side> lower rear control arm. Basically, the lower suspension balljoint. This will result in an MOT failure if any play is detected, but sometimes they are noisy, but will not show any noticeable play.
If the garage spotted them, I'd consider replacing them, possibly yourself, if you're handy with tools - this will save you a few quid. Parts are not cheap, esp from Audi, worth looking at places like
www.eurpocarparts.com,
www.gsfcarparts.com and phoning your local branch for a quote/availability.
Good luck!