Is your power steering a bit jumpy also when cold? Might not be.
The aux belt tensioner on mine had sized. I would check yours - the roller was ok but the tensioner was not taking up any slack.
If it is that to replace you need top put the front of the car into service mode to access everything.
not a hard job just a bit time consuming. audi wanted me to buy a new tensioner and bracket (excluding cost of belts) for about £200 plus the vat. The part i got from CES was about £60. belts IIRC came in about £25 for the pair.