Just seen this thread!
I had a similar issue on my A5 sportback.
It's a motor/servo arm motor (can't remember the proper name). I believe there are 3 motors on the drivers side and the one that needs changing is the most difficult to get access to.
You don't need to remove the whole dash as the Audi instructions say, you can remove the dash panel under the steering and the side below the centre console and get access.
You need to remove one of the other motors to get access tot he one to be replaced. It's a tight fit but possible.
There's a guide on youtube somewhere.