I have to retract my recommendation for a button-integrated reversing camera (see post #30).
After less than year-and-a-half, I had the cam going blank, on and off, and a boot/tailgate unlock problems for a day or two, and then it seized completely, and wouldn't open, and the cam was off.
I reached the manual override from inside the car, opened the tailgate and investigated the problem, initially suspecting a screenwash leak.
Turns out, the water got into the unlock button, and sneaked up to the wiring harness plug (not possible in the OE unlock button, as the pins are sealed), and the camera. Ran the diagnostic to confirm:
Removed the button assembly, cleaned the plug on the harness, and fitted the OE button in. Cleared the above error, and it didn't come back.
Took the integrated button apart, and this is what I saw:
This is really bad manufacturing quality - to fail a simple waterproof requirement like that.
The camera was damaged too - moisture got inside and destroyed the tiny PCB.
So I ordered a simple, metal-cased reversing camera, which required no modifications, other than a self-adhesive rubber pad:
Fitted this, between the button and the right mounting screw, and was pleasantly surprised by the quality:
Apologies - forgot to take a pic of the cam in situ - will do, once it stop raining (around July I hope).