Purchased the gear box and prop today.
Carefully soldered the new motor in, taking care to match white to white and black (new) to red (old) motor to ensure correct polarity. Covered the joints with some ultra thin heat-shrink tubing I thought I'd never use.
Ready to have the prop attached. Notice (barely) the threaded shaft. It is right hand thread - I at first thought it might be left-handed, but I think I over analyzed that too much.
Attached the prop.
When I tested the motor, to my horror it spun BACKWORDS!
Let that be a lesson to everyone - don't assume the wiring on these motors is correct, test the connection before making it permanent. I had to carefully cut the heat-shrink off, unsolder the wires and re-solder them back together.
This time it spins the correct way.
A bit of white glue to hold the motor back in the mounting holes and we're ready to fly again.
Will see how it goes on Monday.