I think that Holdsworth and Holdsworthy may be two same company, Holdsworth being the frames and bikes and Holdsworthy the catalog branch of the company.
I have a bike parts catalog from 1965-6 published by Holdsworthy. The catalog is called "Bike-Riders AIDS" and is published by: The Holdsworthy Co. Ltd., London S.E.20, Wholesale distributors of lightweight cycles, accessories and clothing to the retail trade.
The prices in this catalog are enough to make you weep. How about a nice Campagnolo Alloy Cotterless chainset complete with bottom bracket and 44-52 rings for 240/- (two hundred and forty shillings old money, or twelve quid, that's about US$22.20 at todays exchage rate!!!!).
Brian Booth
Toronto, Canada