[Arran]

 It's been my experience with battery operated radios that they are really not that hard to get playing, that is once you can come up with a suitable power supply for them. Fortunately for almost all battery operated tube radios of the 1940s through the 1950s, they were designed top operate from standard off the shelf batteries. Typically the newer ones will have an "A" battery of 1.5 volts, and a pair of "B" batteries of 45 each totaling 90 volts. The older sets from the 1930s usually used 2 volt filament tubes, so they needed 2 volts for the "A" side, but for the "B" side they typically used a combination of "B" batteries adding up to 135 volts at the high end, 90 volts in the middle, and 45 volts at the lower end, some weird sets used 22-1/2 for the lower end B+. What is often different with 1930s battery radios is that they required an independent "C" supply for the tube bias, in many cases they used just one "C" battery, but some used two or more.
 If you design a battery eliminator the right way you can operate any battery powered tube set from the 1920s through the 1950s, though you can design a simpler one dedicated to a particular set as well and forgo having adjustable voltages. The nice part about battery sets is that you can use mostly salvaged or junk box parts to build the power supplies since the voltages and currents are so low, also most battery radios have such a low number of operating hours on them that the tubes are often almost like new, and the sets will play without being recapped, though I would not trust one over the long term that way.
Regards
Arran