I've done a bit of research and it seems that this isn't an uncommon problem. I've tried some wd40 on it as per some of the suggestions I've read but that didn't make any difference (other than staining my boot lining! ) so I'm looking to actually replace the part. I've spoken to my local Audi and they think the part may be 4F5827505D but I just wanted to run that past the gurus on here before commiting to actually ordering one? Thanks in advance!