^TWR, Yes I agree, but the questioner was saying that there has been a recall of USA Minis with this fault, there have only been two recalls of USA Mini's, one for an airbag fault ( that is the computer chip one) and one for power steering faults. None for gearbox faults as is the case here.
For £2250 you could fit a complete reconditioned engine and gearbox !
A 'clunk' when driving is, as you suggest, more like a drive shaft fault.
jamesnan, do you know a local independant garage with a good reputation? If so take the car there and ask them to look at it , no need for a main dealer with a 5 year old car.