MGOC Spares had a discount on new, hi-torque starters. So I bought one.
The new units were much smaller and lighter than the old. They also promise better performance, lower amp draw, and more reliability. This tackled two previous issues I'd experienced with the starter: 1. I had had the starter "stick" onto the starting gear. This made it inoperable and left me stranded on the side of the road in a busy Cornish town. It turns out that this is an easy fix, once you know the trick: simply turn over the engine by hand to unstick the starter and allow it to reset. Took the AA man less than two seconds! 2. When the car is hot, it sometimes takes a while to start. A newer, better cranking start should both shorten that time and - given it requires less power - give the car more juice.
I sadly didn't seem to take many photos, but the removal/install is easy: 1. Remove the bolts and unplug the wires. 2. Remove starter 3. Installation is reverse of removal.
This process did allow me a good look at the ring-gear teeth which - to my untrained eye - look fine-ish.
The new starter appears to have solved the above issues: it sounds to be cranking faster (though, this might just be a different noise of the starter?), and I've yet to have the hot starting issues - whoopee!