Found this on the bbc site, its the MOT pass/fail stats for all cars during 2007. Thankfully Alfas come high up the list alphabetically (if not for reliability!) (or should that be alfabetically!) so you don't have to scroll down much.
I haven't had chance to look properly at the figures but a few things immediately strike me:
1 - The Failure rate of GTVs is quite a bit higher than Spiders - A result of spiders being more of a "fair weather car" and therefore used less?
2 - I'm not sure how this sits with the DVLA registrations thread - There appear to be quite a few more cars taking MOTs than exist! I guess there cars may be tested more than once in a year.
Any way thought it might be of interest.