I think the tale is not straight forward and quite interesting . I can't remember the details but know I found them easily .
I have an early 80's RJ Quinn that was almost certainly built in the Holdsworth factory .
Lots going against it but if you need one this big the choice is , er , tiny :)
https://www.ebay.co.uk/itm/196143800676?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=0PTvluIMRfe&sssrc=2047675&ssuid=T1RnPK_uSiW&widget_ver=artemis&media=COPY