Hi Everyone,
Thank you for all the kind words of advice. I am grateful, especially so for the warnings and advice about safety and high voltage. It is heeded.
The good news is that this issue is now fixed.
I replaced all of those Hunts and that 220k resistor that was mentioned higher in this thread.
The volume is now as I would have expected to be
Funnily enough this also had a tape when I got it, it was made by a brother and Sister one Christmas Eve who were staying at their Grandparents house and speculating what Santa might be bringing for them. They also did some jokes and some singing before the inevitable arguments leading to the recording being stopped. Really interesting from a social history perspective.
Thanks Again