Hi Francis, I applaud your wish to maintain a degree of originality and may be a much simpler task where the manufacturing techniques were somewhat more..err..uniform than they may have been at the MMC...? Over the years I have observed all sorts of attempts to relate Morgan wiring diagrams to Morgans with issues resulting in a measure of frustration. My +8 Morgan was built in the mid 80`s and the wiring diagram in the handbook does not match that which can be found in the car, not counting wiring alterations of course.

I guess with everything switched on it might be possible to measure the current draw across each of the fuses them being removed and an ammeter put in circuit in place for each test..?

With a bit of luck the colours of the wires should guide you towards the components in each circuit to give you an idea of the normal current draw...?

https://www.gomog.com/allmorgan/LucasColours.html

Good luck.