Bongo Fury

I'm looking to trace the wire that provides power to the light n the AFT, the earth (Black with Red band) is simple,

The v+ is Red with Black band, I assume it's bundled in with the wires that run into the AFT at the rear of the roof, then somewhere within the body of the car up to the fuse box. Looking to fine a convenient place to make a break in the circuit to wire the AFT light into the leisure battery, same question for the interior light really (one on the under side of the roof boards, what have you guys done?

Oh, and the 12v outlets, blinds & finally in dash dvd (that ones easy).

I've managed to identify the fuses that supply power to interior lights, in dash dvd, blinds etc. Thinking I may me able to pop the fuses out and pop a spade connector taking 12v from leisure into the spade terminal on the fusebox. Obviously I'll fuse the inputs I add to the fusebox.

That is the normal method, add a new fusebox to the L/B with at least 4 positions, then run a a 4 wire cable down to the old fuse box and terminate in spade terminals, move the fuses from original to new box and plug the spade terminal into the lower of each of the 4 fuses (Top Left, Top Right, and the two 15 Amp Blind fuses). That way no breaks in the original wiring, it can be put back to original setup very quickly and looks neat!

Thanks, that's what I need, confirmation I wasn't barking up the wrong tree totally.

Final question for now (promise), what rating wires do you guys usually use?

The wires should be at least 1.5 times the fuse rating so I would use something like 25Amp which would be 2mm² for thin walled cable as three of the wires are 15 Amp rated.