Not really engine related (should be in general land rover or defender/90/110)

but here goes:
Green/Red- Left indicators
Green/White- Right indicators
Red/Black- Left tail lamp
Red-Orange- Right tail lamp
Green/Purple- Brake lights (both)
Red/Yellow- Fog light
Green/brown- Reverse light
If your tail/brake lights are anything like mine, they'll have green, red and black wires. Black is earth, red and green are the connections to the brake and tail lights (can't remember which way round it was). There should be connection blocks in the rear corners of the tub. You'll find a couple of spare wires as there's connections for fog and reverse lights on both sides (they're the other way round on LHD) plus a feed or two for the towing electrics.