Jerry. Feked have very few Cycle thread bolts and list mostly complete sets, e.g. Triumph Cyl Head set without any indication or dims or what the set comprises. I've emailed them.

Alan & Steve. I've looked on their websites and emailed them. I didn't previously look at Acme as I was under the impression that they only had s/steel.

All suggestions much appreciated.
I've emailed all the above as having spent most of the day on the blower not only am I losing my voice but my ear's like a braised lamb chop.