The rear lights on the manta ray are hella's the wires have been cut off and I have tails poking out. The stop and tail lights have one black wire and two green ones, I guess black is earth and one green is stop and one green is tail? The N/S indicator has one black and one green, but the O/S has one black and one yellow, is it normal for earth s to be black?  And is it normal to have different colours on either side of the vehicle.. If I earth the black and then feed each othe wire with a crocodile clip from a wire from a battery I should be able to work it out by seeing what lights up , yes? Or any better route to go down. Many thanks.

What is confusing is that VW use Black as a 12v positive ignition live wire and brown as the earth 

Some early Vauxhall stuff is also know to do that as well   

You will find white earths on american stuff. As you say the only safe way is testing on the battery although with a insulated plastic body buggies are forgiving Ive come across lights with the casing live before now.

Right, thanks chaps, there is no existing Vw wiring left,bar the indicator stalk, rear lights are aftermarket so should be not too bad to work out. A friend who has done a fair bit of boat wiring and cutting into looms when converting cars to LPG is coming to help sometime, so for now I am just getting all the lights, switches , fuse box and relays in position ready to between us join them all up.