My Boc is now on about 3k - the quoted mpg figures are possible, I think, but the best I've managed on my 30 mile drive to work is 41mpg usually more like 35. It's all back lanes though so not too suprising. The mpg has defo improved since new though. So far motorway mpg seems even worse - but I guess would be fine if you stick at 70.
I've found that you really have to keep your right foot very light to get any kind of decent mpg. My old Golf diesel would range from about 45mpg if you gave it a lot of stick, to about 55 if you nursed it. The Boc is much more sensitive - more like 20mpg if you rag it and 40 if you are v v v careful. Guess that's a big difference btween petrol and diesel.
Anyway - worth a few extra quid on fuel for the extra grinning when you hear the rasp and feel the acceleration.