Thanks Lenny. That was some great sleuthing on a Sunday, hope you have some beers going. I have used your drawing and a Snap On one i found on the net, along with some point to point testing and worked out the following;

6 pin Plug on engine bay side of loom with 5 x wires
Red/Black D1 Power 12V+ to EFI relay contact
Green/White A1 Fuel Pump Relay 12V+ to coil
Pink/Blue C1 EFI Relay 12V+ to coil
Red N/A Oil Pressure Switch (to injector voltage after EFI relay)
Violet N/A Oil Pressure Switch (to Fuel Pump Relay)

8 pin connector on engine bay side of loom with 7 x wires
Brown Still no idea?
Brown Still no idea?
Green Still no idea?
Green Still no idea?
Blue Still no idea?
Green/Black A5 A/C Relay (assuming 12V+ out?)
Blue/White A8 A/C Cooling Fan Relay (assuming 12V+ out?)


There is also another plug, which is on the inside of the car section of the loom (not far from the ECM plugs) with the following;
Brown/White A12 Brake Fail Lamp
Pink - C1 Ignition Power 12V+
Blue - B1 A/T Control
Violet/White C12 Speedometer
White/Black D6 Diagnostic Enable (to diagnostic connector)
Yellow/Black A10 Trip Computer
Red/Black C11 Diagnostic Data (to Diagnostic Plug)
Brown/White A7 Engine Check Lamp

I will get to the bottom of the 5 x still unknown wires, but considering the 3 x plugs above are the only ones that would connect to the Commodore, this must constitute almost every wire that needs to be considered when slotting this drive train into an old car.