Digsy,
The alloys in my post "Please help the newbie II" have bolt on fitted. Took a complete novice like me hour and a half to do the lot, no problem and easily reversible. I got the bolt ons from www.dp-motorsports.co.uk (think they are in Scotland) speak to Dougie - very helpful.
No drilling etc. Just had to remove one small bolt from the front discs.
R