I'm not sure about the exact business arrangements, but certainly some of the RSC stuff was built in Leeds as one or two of the local hams worked there. G3TDZ springs to mind, as he used to publish various amateur projects in SW Mag. There was a guy called Trevor who managed the RSC shop in the Grand Arcade (or Victoria arcade?) in Leeds before moving on to
Globe Scientific owned by a guy called Gerry, who were popular purveyors of SW radios, car battery chargers (
built by schoolboy me!) and unmarked transistors
.
I think RSC wound all their own transformers, both for use on the amps and for sale in the shops.