Tvr chimaera starting problems this weekend...

Didn't get that much done on any of my stuff this weekend but an interesting one helping my dad out with one of his cars,he's had problems with the fuel pump relay on his tvr before but the usual fix of swopping the relays around didn't get the pump buzzing.
After moving his austin healey out the way (it's a hard life) we had a little look...

After checking all the fuses were ok i tried checking the terminals for the fuel pump relay,using the neutral on pin 85 i found there wasn't 12v on pin 30 or pin 86 to power or switch on the relay? At this point while i was turning the car over a bit of smoke seemed to come from under the bonnet, my dad muttered it's been doing that for a while, using a torch we could see a large diameter cable with no insulation and a melted wiring loom, bugger!
Figuring anything can be fixed i started stripping the plenum chamber off the engine to get a bit of access, the main battery to starter motor cable was so burnt i could pull the 2 halfs apart, surprising the starter worked at all or more worryingly that it didn't catch fire! The loom didn't seem to badly damaged other than the outer conduit, a check at halfords pulled a blank for battery cable so that was it for one day!

Luckily i had to go to our office sunday morning for a few hours and under my bench was a 5 metre length of 16mm2 battery cable i'd bought for the split charging system on my van, it was slightly smaller than the original but we took a committee decision (british leyland in the 70's style) and decided it'd be fine, at least an hour of wrestling and we had power (again) Still no fuel pump though?
To confirm the pump worked we bridged the pump supply from the relay next to and it started, during our coffee break i scoured google for a tvr chimaera ecu wiring loom diagram, all i found were people asking for the same on forums! Eventually worked out the ecu loom is a range rover standard item, on a pdf website there was a 1992 ecu diagram which i figured must be close. The colours were wrong but the gist of it is probably the same.
This time we went a bit deeper into the relay wiring, and put the black lead of the multimeter on the negative of the battery, now there was power on pins 86 and 30?
It turns out there was no neutral going to the relay, with a wire run direct from the battery the pump worked a charm, but it then wouldn't start! After a bit more multimeter work we realised that a suspect relay had been put into the main ecu slot next to the fuel pump relay, so original fault was a duff relay and no neutral. Whether the relay blowing took the neutral out we're not sure,that neutral comes from the ecu direct. With a different relay job done, fired up a treat.