Luckily they are very simple machines to work on. You can take one to individual components with a 9mm to 17mm spanner set, screwdriver, hammer and chisel.
I will need a wiring diagram though as, well, it was not exactly wired up properly when I bought it so I just gutted it of 25+ years of bodged wiring.
I feel a little lightheaded now as I just spent five hours removing what turned out to be six (six!!) coats of different coloured paint with thinners. Looks like it was something similar to British Racing Green originally. I'm going to spray it either that or a nice Orange.
Here's the frame (almost) at bare metal.