The new part arrived and wow what a difference! No matter how much I tinkered with the old one, I'd never be able to get it as good as the part so decided to go ahead and fit it. Having just done a road test, the difference is night and day. The new part is really rigid and doesn't creak at all, where as the old one was really flexible.
For anyone else experiencing this issue, particularly with a 2-3 year old car, I can't recommend changing the part enough, the improvement is huge. It cost me £319 direct from Audi and arrived the following day and was very easy to fit.