thanks again both. i didn't remove the wiring etc. it was all disconnected and a jigsaw in a box , but with a poor picture to copy
in fact i have a feeling i didn't have a harness at all and i got the harness from big AL with other Gordon spares . it is however definitely an original cloth bound Gordon harness and the "puny" starter cable is the correct length and in the correct location to reach from solenoid to Lucas starter motor - perhaps this is in fact the reason so few Gordons survive . the possibly very hot starter and solenoid is actually fairly close under the bonnet to the fuel tank too 
Having just completed starter wire repair/ replacement on my Trojan that had melted, I can attest to the fact that the wire gauge shown in your most recent photo of your newly prepared manual solenoid is far more correct. I would not recomend anything less than a number 10 gauge wire and ring terminal fittings.
With Al's incredible memory of voltage regulator tab identification numbers and even wire colors, I was able to figure out that on my Trojan the wires to the starter and wires to the generator had been switched by the previous owner, which resulted in a recurrent meltdown of all the insulation off the misguided wire.
This was especially challenging to diagnose, as electricity going into the generator coils did result in what appeared to be sufficient engine rotation speed, but alas with too much resistance through the smaller gauge generator wire, and possibly with a reversed direction of rotation.
I always heard that Gordans self incinerated due to insufficient engine compartment air flow. But after seeing the wire to the starter that you've shown, I believe it more probable that this could have served as an ignition filament for gas tank vapors.
After all if it could bring down a jumbo jet, why not a Gordon?