Drivers door speaker issue/fault

I have been trying to fix an issue where I loose sound completely on the driver's door. Having gone to the expense and time of replacing the entire drivers door harness and testing both door speakers (took 3-4 hours), I have established it isn't a physical issue. When I run a scan (in obdeleven) the sound came back crystal clear. The persistent faults found are attached. When I shift to reverse and the (aftermarket) camera comes on, I lose sound in the driver's door again. Connect/scan and it comes straight back. I am now convinced this is a coding issue. It seems to think there is a 'media player' installed but there is no such module. It has also recently lost the steering angle and distance markers on reverse camera screen (they were originally there). Any suggestions would be greatly appreciated.