Serveral MINI-friends here in Sweden is sharing this problem (including me), but one of the guys were told by a mechanic at a MINIrep that there is something to do with the valves and if the car hasnīt been "using the revs so much".
This was the explanation he got, still it disappears after a few minutes of running, MINI has not come out with an alert, so if this should be a major problem (such as safety or severe risk of damage to the engine) I am sure MINI would call in all cars to get it fixed soonest.
The sound is a bit annoying when starting the car, but it soons disappear - just remember to use the revs, guys and gals
