[HPsauce]

A longish messy thread, so here is:
Summary of a reversing camera installation - in a car WITHOUT OEM TV.

Camera from eBay/China, 45 degree downwards type, is mounted centrally immediately above numberpate on boot lid. It is almost totally hidden by the numberplate surround when this is refitted.
Plastic numberplate mount removed and hole cut to fit round camera; camera is fixed to metal of boot lid using rubber well nuts to avoid corrison issues.
Camera is mounted on a rubber backing plate which both provides a weather seal and allows slight adjustment. Final position just shows the rear bumper at the very bottom of the screen.
Radio link from camera mounted inside boot lid behind trim sends video to receiver near driver, presumably helped by my car having a ski hatch. It and camera are powered from the reversing light circuit which is easily accessed with the trim removed near either reversing light.
The radio sender I bought provides a power output to the camera so wiring them both in is very simple indeed.
Reversing lights had already been replaced with LEDs so plenty of spare capacity in the circuit.

Radio receiver and T-ERA video interface (now NLA but there are alternatives) to RNS-D mounted in drivers footwell behind knee panel.
Power supplied from RNS-D circuitry and relay(s) using the following sources:
1. Permanent 12V from RNS to CD changer.
2. Switched 12V (CD changer circuit) activated whenever RNS is on.
3. Reversing light power available at RNS (actually in the same circuit as in boot lid)

When RNS is on #2 triggers a relay to send power from #1 to the video interface via a fused lead.
(This supply is also used for the DVB-T tuner, without this option the video interface could simply use the same supply as the radio receiver)
When Reverse is selected #3 supplies power directly to the radio receiver.
(The same circuit also activates the camera and transmitter in the boot lid)

With DVB-T installed a second relay is used, triggered by #3, to switch the CVBS signal to the video interface between DVB-T and camera.
The DVB-T sound is connected at all times so that audio (TV or radio) is maintained when reversing.
If you are not using (or don't have) the DVB-T you would need to select TV input on the RNS-D after selecting reverse.

And recalling my "objectives" from post #1:

Originally Posted by HPsauce

Here are some parameters:
1. Ideally a camera that shows the rear bumper at the lower edge of the field of view.
2. As automatic as possible to turn on when reversing, possibly with an override switch to manually turn it on.
3. I have an RNS-D but NO TV tuner.
4. I do have a TV/video input adapter (which does work when installed) bought to enable use of a DVB-T tuner.
5. This adapter has a switchable option to display video when moving

1. Achieved (mounted centrally above number plate)
2. Achieved (in conjunction with DVB-T tuner)
3. Achieved (Digital TV added, new dual diversity tuner)
4. Achieved (after some tricky wiring repairs, both camera and DVB-T use this)
5. Achieved (bought a Kufatec loom, adapter option doesn't work with RNS-D).