How to recode head unit to car?
 

Hello, I have a 2007 R55 Cooper S Clubman. I took it to BMW recently as I have no gongs, can't use my Bluetooth, microphone etc or aux or USB port. The guy who had my car before swapped the stereos out, so my car has another minis head unit coded to that car. I have radio and DAB. BMW can't or won't reset the head unit. How is this achievable? I'm at my wits end. I'm in the UK.

Thanks