[Arran]

Well the Bush radio I mentioned, as well as the Phillips "Philleta" I have, had a large wire wound resistor with taps on it, the Phillips was designed to run on anything from 250 volts, down to 120 volts, the Bush is more like Mike's Telefunken, the set was designed to run off of voltages ranging from 200-250 volts. Murphy was another British company that made a lot of hot chassis AC/DC sets, they also liked using rubber/gutta percha covered wire apparently, which likes to disintegrate like the stuff used in 1939-42 Philcos.
Because of the electrical code in Canada all of the AC/DC sets had a floating chassis, and they didn't even allow those until around 1940 or so. So the only hot chassis AC/DC sets I see are imports from elsewhere, usually the U.S, but it seemed to be the prerogative of the manufacturer, Brand Z did this, as did Fada, but Philco built floating chassis sets regardless of whether they were US or Canadian made. I have an Airline 94BR-1526 from around 1949, and they ran the B- in a rather interesting way, they used a length of 14 awg wire and ran it from the power switch, to another fixed point, below the tube sockets, and then tied all of the electrical grounds onto it.
Regards
Arran