Tested the 1st and 3rd sensor is broken. Looking from top of car, 1st sensor being top left going clockwise...

 

Just an update.

The 1st & 3rd is not working, so I replaced the first one only with 2nd hand genuine part.
It seemed to have fixed all the issues. Parking sensor display works, the camera message is gone and the radio doesn't switch off after 30 seconds anymore...