Not that I can help with your issue but my other half has an R53 mini and we're always having problems with it
Just got off the phone with the garage this morning and it needs a new crank pulley at £320 odd fitted recently had £500 worth of suspension work done and then before that had around £800/1ks worth of other stuff replacing (steering pump leaking etc..)..
It still needs the aircon fixing but apparently the part is about £800 so she will just have to drive with the windows down if she's hot
It's not been cheap ownership, that's for sure.. The sodding thing has only done 50k miles.