Just a note which may help others, as I always search the forum when the bella decides to rebel !! usually just about when I am considering buying new head unit.
Anyway driving last week, car cut out totally, manage to pull in and restart car, drove for about another 1/2mile then died again, and would not restart. Whilst waiting for recovery plugged in the scanner and checked codes. P0335 and P0564, plus another I can't remember to do with crank senor performance.
Not sure why 564 came on, but recovery guy suggested it may be on same circuit ??
Anyway new crank sensor fitted (Alfa £45 + fitting needed starter motor off), and codes cleared, all good again
talking to mechanic seems the magnetic sensor is usually OK but the resistance changes with age until it goes out of tolerance and computer decides no longer to read it .. but looks like HU will have to wait until next month again.