From what I have read elsewhere, they sourced some frames from Mercian and possibly George Longstaff - perhaps they did make some also? I really don't know much about the company, but would like to find out more.
I recently put the frame for sale on
eBay (I withdrew it from sale before any offers were made as I couldn't bring myself to sell it😊).
One of the potential buyers offered to try to find out about the frame, but I haven't heard any more.