Appreciate your input @Deano. The pdf has EFI circuits? So far none of the diagrams supplied match what I have :-(
I reckon my dilemma is the two rear harness's I have. The rear harness that matches the Gregory's does not mate with the front engine/dash harness (which does match the Gregory's and I have managed to install and connect most of it to gauges, ignition etc.).
I think I'll run with the current engine/dash harness and join the matching rear harness (which does not match the Gregory's wire colours at the tail lights) and then buzz these connections out when I have some power back there. Can't be too difficult adapting the harnesses in the boot section.
Out of interest- the two rear harnesses are quite different in the boot section. The "wrong" one is neater in that it comes through the rear firewall and goes to the LH tail light, then through the rear scuttle to the RH tail light powering the number plate lights on the way past. There's a section from there that I think is the boot light.
The "correct" harness comes into the boot and splits to LH Tail light, then a long section at the split heads over the top of the boot (I presume) to the RH tail light, powering the boot light on the way through. There is a heavier twin wire around that section that I don't know what it does yet.
Worst part of the build yet! I have ordered a Haynes Manual to see what confusion that brings!