Hi Martin,
I've been having a load of problems with different Audi dealers over creaking, but also do to with the Track (Tie) rods on the steering, these are the bits that connect the steering rack to the wheels (quite important really).
I was told at my last service that my drivers side track rod was the worst one they has ever seen and non of the mechanics would drive it. also audi have in the service manual to check the track rod ends at ever 20k service to see for play in them, if it is just the ends then it's not that big a deal, in fact even if it's the whole rods then again not a big deal but the cost can be ****** high as you'll need a 4 wheel allignment when they are changed.
hope that was some help, i'll be getting told the passenger side needs doing tomorrow when it's serviced next...
ps, the symptoms should be slight juddering when not accellerating over bumps if its bad... or vibrations trough the steering