Thanks for that Eddy,

The smoke smelled like oil.

First job will be to take the guts from the new starter and fit them into the old casing, using the original solenoid - maybe there's a difference in casings that I can't see.

If that's no good then apart from swapping out the flywheel, is there anything I can do to try to fix the flywheel? Maybe try to file off burrs? Is shimming the starter a half mm or so just on the flywheel side a reasonable idea?

If not, I'll have to remove the transmission and change out the flywheel. Are there any pratfalls / hidden problems with doing this, and is there anything else should I consider doing while I have the transmission out?

Apart from working on smaller things like brakes/carb/dist etc, I'm a complete novice and this would be my first attempt at something as big as this. Aside from my wrenches and socket set, what tools would I need for the job,... trolley jacks? Life insurance?
I'm reasonably mechanically competent, but have no knowledge of this job - given that I don't break anything (ha) and that nothing goes wrong (hahahahahaha) how long can I expect the job to take?

I'm hoping it doesn't end up like this 4x4 wire - old thread