General thanks, and any recommendations for special tools
Quite a bit of good advice given here already - thank you everyone, you're awesome.
Access to a metal workshop is not something I can easily get, I'm afraid. Good to know that for some models that's needed, though - it will save me wasting time trying things I can't do yet... I've got a set of Chapman's screwdriver bits on the way (the 8900 set) and a pretty strong husband but not much in the way of other tools. If any of you have recommendations of "Well, I wouldn't be without my xxxx" then please let me know what they are. If I already have it I'll assemble it into my "machine kit", and if not I'll keep an eye out for them.
Thanks again... Megan