I've looked into this further. I still haven't had a chance to do the screw mod though. However, I had a look at the arch the other day to check everything was alright, to find there is some tyre rubber on the arch lip, so the screw mod alone isn't going to cure the problem. I've asked a local guy if he had any issues when he ran a similar wheel/lowered setup on his mk5, and he said his wheels easily tucked up into the arches, without fouling on them like mine are. We reckon it must just be the wheel alignment. I didn't think there was much if any camber adjustment on the front as standard, is that correct? I have read that the subframe can be slid from side to side though, in turn affecting the camber, reducing it one side, increasing it on the other. Is that true? If so, it would explain why one wheel clears the arch and the other doesn't. How easy is this to rectify? I read from the same source it's something VW refuse to undertake, which doesn't fill me with much confidence.