Guys, you are all diamonds, thanks for all the help - I have no reason to dis-trust the garage, and was not expecting them to have caused the problem, just wanted to be sure, but will still get a 2nd opinion, probably from RSD in Daventry (
http://www.rsdcars-uk.co.uk/) when I get back from my trip to the Monaco GP
Will have a think about what I am going to replace it with, considering a D3, but might move to an X5/Q7 instead, or might just buy a crappy old banger off ebay while I think about it.
Pls do nudge me though if anyone knows of a well-specced older D3 coming up for sale. (No cream or silver/grey leather though thanks, black or brown only)