[SimonP]

Danny,
On the donor, the "pull to flash" main beam switch works off a different supply to the "centre" (dip) and "push back" main beam switch.
Before you tear any more hair out, have you tried operating the lights with the ignition in position 2 (engine run)?

I don't know the Pilgrim loom, but I'd guess it was wired the same way.
How many wires do you have on the Pilgrim loom to connect to the main/dip stalk?

Simon.