Made a start this morning, stripped out the dash and it's a bit of a mess with wires all over the place wires spliced all over and dubious looking connections. I've mostly been prodding at wires, working out where they go and either labelling them or removing them. Glad I bought a label writer now!
I've removed a cigarette lighter and a huge load of stereo wiring and it's starting to look a bit better.
The next thing to think about is earthing. With it being fibre-glass there aren't the usual earth points on the body, there's a large earth cable to the engine block then a smaller cable to a junction box in the corner of the boot. Everything is ultimately earthed to that box via a handful of 2mm ish cables. It would be miles neater to have an earth point behind the dash, so I should probably run a 10mm cable from the engine connection to a suitable junction box behind the dash and start tidying the earths. Same situation with the lives, though I've not traced all of those yet - big loop of cables from the rear corner rather than one short fat length from the solenoid.
The fuel pump is powered by two wires running from the front of the car, that was spliced into a random switched live. So that is also earthed by doing a full loop around the car and back to the battery negative that's 10cm away from the pump!
The rear loom is a mass of wires all tied together, half of those aren't connected to anything too.
So loads to tidy and correct and a much bigger job than I was aiming for, but it's only to do once. I've been working while my daughter is sleeping in the workshop, she's awake now, so I might not get much more done now.
Recommendations for a suitable junction box? Can I get a fuse box that'll take a single feed and distribute to a number of fuses?