Sorry retepknarf, I've just seen this post.
My 1963 Radford just seems to have extra wires added. In the 70s the lamps were replaced (by W&P) I think, so there's a complete jumble of different sizes & ages of wires.
The ones installed by Radford (I assume - maybe someone else can verify?) are braided cotton bound. I'll try to get a picture if you're interested.
Spotlamp runs from main full beam circuit & Fog from a switch on lower right dash rail (on the "Motorway" type dashboard - not checked if there's extra relays, or even a connection for the fog directly from fuse box or lighting circuit.
by the way - I love the detailing on your engine bay mk1leg - what paint did you use for the master cylinders / relays?
One day I intend to bind the wires with a fabric loom tape but there's a heap of jobs to do first......