[Arran]

Flexible resistors seem to have been somewhat of a fad in the mid to late 1930s, I think that the reason they were used was so they could install a higher wattage resistor in a tight space. I've often found them installed between pins under a tube socket where a rigid wire wound from that day would not fit. They also have a nasty habit of cooking themselves to death, the casing was mostly made out of "spaghetti" type tubing like they used to use around capacitor leads. Eventually through heat and age the tubing breaks down and starts falling apart. I would replace the flexible resistor with a modern wire wound or metal oxide resistor, they are much more compact then they used to be.
Regards
Arran