Thanks, Dave, that's really helpful!
Fitting myself probably isn't on, much as I'd like to. I've got recurring tendon problems in both shoulders, which I keep setting off by lifting things that I probably shouldn't lift, because I'm too bloody-minded to recognise my limitations.
As I understand it, a gearbox is a two-person job even with the right kit, which I haven't got. And as gearboxes go, I imagine a Volvo one is going to be on the heavy side. So I think this is one for me to man up and pay a professional!
Luckily, my local indie is a good guy, and happy to treat the Tank with the TLC she deserves.