I have had a win. After triple checking everything I found that the reverse polarity diode had a break in it so I bypassed it with no luck, checked voltage out of the relay near the battery and the orange wire was reading 4v and slowly dropping off, replaced relay with no luck but had the full 12v out of this wire now.
Sent the ECU down to Adelaide so my daughter could test it in her car and the ECU ended up being fine. She posted it back and I fitted it back in my car.
At this stage I had lost 12v at the injectors and noid light wouldn't flash, not sure how I lost the injector pulse? I removed the earth for the ECU that was bolted to the engine mount to block and moved it over to the block and I had injector pulse again, at this stage I had the top half of plenum off and rail out and verified that injectors now worked.
Bolted it all back together cranked it over for 20-30 seconds and it fired into life.
Not sure why I lost injector pulse and how the earth went bad but she is now running.
I believe the original issue was the relay and broken earth from it because at that stage I had injector pulse, with the earth fixed and a new relay I must have came across a second issue when I lost injector pulse because of the earth to engine (didn't do anything to make it do this).
I hope this helps another member out when searching for similar issues.