Wiring source for a TR8

I am looking for a source of an alternator wiring harness for a `80 carbed
TR8 with a/c.  I've checked all the usual suspects (moss, rimmer, victoria,
etc.) and nobody seems to have one around.
Since the chances of finding a supplier seems slim, can anyone point me to
someone who will make a harness like this?  As I understand it, british
wiring sizes are different than AWG so even finding the wire could be a
problem.
Thanks for any info,
John