[Arran]

Terry;
  Most of those battery sets with the low current tubes perform pretty well given the limitations, about the same as a three way portable that uses all battery tubes. I've never worked on this Philco model but the on/off flag is a pretty common feature on many battery sets, I had one where it was worked with a short piece of dial cord attached to one end with the string wrapped around the volume control shaft , and a spring on the other end of the flag, it took a few tries to get that fixed. One common feature of just about all of these is a power switch with a very sharp "clack" sound when you turn it on or off, I guess to let the operator know that it was in fact turned off. Some of these sets had dual IF amplifier tubes, not an actual extra stage but an extra IF amp like some 1940s Philco models had, other models had dual output tubes connected in parallel, where if you wanted to save on batteries you could switch one tube off, a lot of thought went into designing some of these battery sets, I dare say more went into some of them then their AC powered brethren at times.
Regards
Arran