Thanks for the answer.
There's no option for media. The most curious think is that if I unpair the devices and pair them again it works, but when I stop the car and disconnect the phone the next time they're connected there's no media. I've tried clearing the cache, reset the car system, installing all sort of BT apps and no joy.
It was working perfectly two weeks ago, and it works with other devices like speakers and headsets but not with the car system. That's very annoying.