I have continuity from pins 16 and 17 to injectors and I can manually signal the injectors on. I've tried disconnecting the throttle switch but I still don't get an injector signal. Something that looks a little strange is pins 35 and 36 (purple/grey and black grey) coming out of the ecu have been spliced in to pin 37 (Red/blue)???

Where are the earth points on the head which you mentioned Andrew?

Thanks