This set was produced in 1944 by 44 different set makers
Rare survivor - the battery Civilian set.
The centre knob is correct - on battery sets it is the on/off switch.
Individual manufacturers used whatever components were to hand so, although all sets are basically the same, there was little consistency in details. Control knobs are one instance of individuality.
Scale shows just two alternative programs.
When a raid was on, the local transmitter would be turned off and (if you were lucky) you could still just about hear the next transmitter up the line.
4-valve superhet; very sensitive and tidy at the back; ready to go
A simple set; built down to a specification and price. Much larger than the mains set so the batteries (not included) could be stored inside.