Quite a bit acheived today. Rebuilt the steering column and refitted it to the car. Trouble is now that the hole in the dash for the column to protrude through is not right. I think that when I took the initial measurement for the hole, the column was not fitted in its best postion. Heightwise it's OK, there's just about a 15mm difference to the left. Thinking that I'd better order the CF dash now, I suddenly had a brainwave. If I am using the column shroud then this will cover any fettling that I have to do to the dash. Dash suitably modified, the steering column fits perfectly with hardly any noticeable evidence of the extra cutting. The ignition switch is now wired in correctly with the 9V ECU fed from the accessories connection. The "ignition" position of the switch provides power to the aircraft switch and the pushbutton.
Had a look through the wiring for the front lights and with a bit of experimentation I can get the headlights to come on. Unfortunately the sidelights and the main beam refuse to work. More investigation needed here, I suspect that there may be something up at the switch end. The indicators and hazards work OK as well.
The throttle cable is fully installed and works a treat :-) The worries about the stiffness in the cable turned out to be unfounded. I will still add a return spring but in all honesty it isn't really needed.