[emeritus]

That looks like the same model that my late father bought in the 1950's. It has been in store at the back of my shed since my mother died almost a decade ago, and is now rather inaccessible. It was working then, but the tuning knobs were reluctant to turn, no doubt due to dried- up grease. That model has a single output valve operating in Class A with a 3W output, feeding a highly efficient loudspeaker. The empty valve holder punchings are probably for the (US) export model that used two valves in a class B push-pull output stage. Plessey made the chassis, and a work colleage gave me a copy of the export model service booklet.