I have look at those wires this morning. From the ignitor's plug to the coil's plug there is one common wire (red arrow) which is direct - it does not go back into the loom.
On the ignitor plug there is one black/white wire (green arrow) which is the same +12v as the one I spliced earlier for the injectors.
From the coil's plug the other wire is also black/white (blue arrow) but that is not the same wire as the one on the injector's plug... although it does go to the same plug at the other end of the loom.
I am guessing that the green arrow and blue arrow wires are from other sides of the IG switch to split the load, as you were saying earlier. Does that sound right?
Should I splice the blue arrow wire to the other IG from the green arrow wire?
Hopefully I you can understand me
Cheers