I have been looking in the areas you have both suggested.
The injector connectors have about .5 volt running to them, not the 12V.
I have been pouring through the online manuals, they have been very handy. They explained how to check the ECU and had lots of wiring information.
The earths on the inlet manifold were brown with black dash, I have cleaned / refitted these. (good memory!)
I have replaced the relays in the footwell with known working relays from the engine.
The diagrams indicate that there maybe a resistor or solenoid between the battery and the injectors. I cannot seem to locate this, I would like to as the injectors do not seem to have the correct voltage. The ECU does not read right across E01 / #10 or E02 / #20.
I hope to find this "resistor" or solenoid to test otherwise the manual says it is the wiring or ECU.