[Arran]

Daniel, Mr. Fix;
The tubes used in this set are "Rimlocks" they were a development of the Phillips group of companies, they used sockets with a collar, and the tubes themselves had 8 pins with a stub or "key" stinking out the side to locate the tube in it's socket. There does not appear to be a dropping resistor in this set, but the rimlocks developed for series string sets typically added up to 120 volts volts with the dropping resistor dropping the remaining 80-120 volts from the power line. However the tube heaters draw about 100 milliamps as opposed to the 150 ma that later North American series string sets typically used. The mixer oscillator tubes/valves in European sets typically used a triode-heptode combination rather then a "pentagrid" configuration, in this case likely a UCH41, though there were exceptions of course.
Whether the chassis is connected to one side of the power line I would have no way of knowing as this is some sort of later conversion, possibly using a "kit" of parts, some manufacturers used a "floating chassis" and some did not. In the case of my Bush DAC-90A it is a "hot chassis" set, and there is a safety interlock on the power cord that disconnects the cord when the back is removed, and the knobs have shafts, with grub screws, that extend inside the cabinet so the operator to reduce the shock hazard.
Regards
Arran