[Arran]

Marion;
Replacing volume controls was something some service shops did in years gone by to make a little extra profit, and it's been a thorn in my side for years. Often the original control likely had nothing wrong with it other then being dirty, but replacing them made more money then simply cleaning them with some spray. It's a thorn in my side because they often did a crude job of replacing the control, or used one of those horrid controls with a "one size fits all" splined shaft. Most of the controls I have to replace are because some shop did a bodge job, of the original controls I have encountered only maybe two or three were defective, aside from the power switch.
Does it look like someone changed the control, such as the wiring looks like it was disturbed? It's odd that someone would have gone to the trouble of replacing one on a battery radio, after post war electrification many of these old sets were simply retired and replaced with a five tube AC/DC set, only the odd one had a battery eliminator fitted. It's no unusual to find one that still has all of the original tubes, capacitors, and resistors still in place, and they often still work if you power them up, barring things like a defective battery cable, or grid cap leads. If you plan on using one of these sets on a regular basis they will probably need the capacitors replaced, at least in the audio amplifier section.
Regards
Arran