Little update, unplugged original immobiliser box and plugged in a spare one I had and it made no difference. Then tested the ecu voltage between pin 19&20 and its zero. Then used a link wire from pin 1 to 10 and I couldn't hear any clicking.

Am I right in saying the ecu relay is under the passenger foot well and is yellow in colour?

Only wire I seen knocked off was a red wire going from the ignition switch area to a new fuse box in the glove box. I couldn't work out what terminal on the ignition switch it had broken off so I've touched it off each of the four terminals and it seems less irratic on the black wire with blue trace so I crimped it temporarily and still no difference.

Again I've checked all fuses and battery is plugged into charger so getting 13v through that, with just the keys in the ignition I was getting battery volts to my starter which I thought would only happen when the key is in the start position.

Also couldn't find inertia switch anywhere and I've got the drivers side kick panel off so I'm guessing it's been bypassed as this car has had a lot of electrical work.

Please help its pissing me off its the last thing I need to do before I can mot it and kick its cunt in.