Hi Grahame,
I have an earlier wiring diagram which does show the warning light circuit.
I tried to send it to you, but the file limitations won’t allow.
If you send an email to helpline@traction-owners.co.uk, I will try and copy it there for you.
One side of the ignition light goes to terminal A3 of the fusebox on the regulator and the other does indeed go to the D terminal of the regulator