The guy tried to explain it - essentially he said it was just a feature of the new engines, all part of the way they work to keep emissions down, etc, etc.
Trouble is we were in a hurry to collect the car on the way to work, having dropped it off to have 12 other issues resolved. As such we didn't have much time to go into it, and I was busy checking that the carpet gap was fixed, the boot alignment was fixed, the boot alarm was fixed, etc.
We did manage to get another R56 Cooper S loaner for an afternoon, though, to see if this produced the noise. It didn't - but then ours sometimes will go for days without making it. Interestingly, it did make the 'growl' when slowing down for speedbumps in 2nd and then pulling away, though.
I guess the bottom line is that we're still no further ahead diagnosing this problem - if indeed it is a problem. But the number of people experiencing it seems to be on the increase. I notice that Paul and Olly have mentioned similar noises elsewhere - see:
http://www.mini2.com/forum/2nd-gen-f...ml#post2975699
...and the post immediately beneath it.
