Does this happen to you? I'm not sure if its my Idrive software or if its my iPhone, but from time to time my BT freezes up the whole iDrive system and I have to turn the car off and turn it back on (as you can imagine, its pretty annoying when you're driving) or wait about 5-10 minutes for it to clear.

Is it worth me bringing in to the dealership or it is my iphone?

 

whoops wrong section, can this be moved to the BT section.

 

See if you can duplicate the issue with another phone. If BT freezes on another paired phone then you can expect the problem to be the car [not necessarily iDrive but the telecomm module].

If another phone functions normally when paired with your car, your iPhone may need a firmware update / fix. In my experience, phone firmware is often the problem. But the step described can help rule that out.