Hover over a wire to confirm the colour
Note 1: Late UK cars seem to have a subdivision of the green circuit with its own in-line 35 amp fuse supplied by the white/brown (ignition relay) circuit feeding things like heated rear window, indicators, heater fan and tach, which leaves the original green circuit fuse (2nd one up in the four-way fuse block) feeding things like reverse lights, stop lights, washers, wipers, and circuits associated with the seat belt warning lamp and time delay buzzer.
Note 2: The junction in the green/brown for the two reversing lights is done with a sealed connection (arrowed below) under the off-side light, and not with bullet connectors. This is because the connection to the light units is with a plug and socket instead of with tails as is the case with all the other lights. A bullet connection between three wires all from the same harness would be pointless.
Note 3: Originally the two earth wires go to a number-plate mounting bolt. Possibly all RB cars but definitely 1977 and later (and 1974 North American with chrome split rear bumper) those earth wires go via bullets shared with the earth wires for the number-plate lamps.
The reverse light switch seen through the gearbox tunnel, right-hand side:
The 2-'pin' (actually two female spades in a three-position holder) arrowed.