Thank you so much Plato! That's a huge help - I'll give that a go tonight and see what I can do. All the technical stuff like that is so alien to me.
Interesting point about the temperature too! When I tried it over the weekend, from the boot fair, it would play then stop after a couple of seconds - only fast forwarding. Tried it last night and it (more or less) kept on playing.
Do you have many Betamax yourself, Plato? Would love to see your collection if you have some