re' ( do I have to remove the entire rear floor and hang like a spastic monkey ).
Well the camera is in the hatch/trunk lid so you won't have to remove the rear floor. Just lie on it on your back and work on the trunk lid over your head in the dark.
Question is whether they run separate wires for the camera or drive its output onto their optical bus. (" Vehicle models from the E65 on,it is the first time for BMW to use fibre-optic cables as the standard for communication between control units. The optical buses in question are the MOST bus, primarily used for in-car entertainment electronics, and the byteflight bus, which serves predominantly safety-critical functions.")
It would be amusing to find a VGA connector back there. Has anyone got a wiring diagram?