Hi Ken, Thanks for that. Back to the post subject ....
Internal Relay Wiring Question for the Headlight Cut:
Is there any difference between wiring the new relay as your drawing or by connecting 86 & 87 (as per) BUT running the diode from 85 to 87?
I'm an electrical neophyte

but that looks like the same connection result. The reason is that the relay I have is a slightly different layout to the one illustrated - same relay and connections but the connections are one to each of the four sides and my suggested wiring is a bit easier space-wise.