Next item was to fix the propeller. Airfix's instructions call for the prop to be installed and then the engine cowl attached, trapping the prop shaft in place. Foolishly, I did this. I think I mentioned earlier that I then broke the assembly loose during masking. Here are the original kit parts.
Giving it some thought later, I believe the prop can be installed from the front, after some surgery, and after the fuselage and engine cowling is glued together; but that wasn't going to work at this stage.
So I reamed out the hole in the front of the fuselage, then went to the parts box and took a broken prop from a Hasegawa B-17 along with two retaining rings. I glued two rings together and filed down the prop hub to fit through the enlarged whole in the fuselage. Then I stuck the prop shaft through the rings and glued the shaft to the Stuka prop.
This is the backside view. Now I can push the whole prop assembly into the fuselage and glue it from the front.
The two rings-glued-together will secure the assembly to the fuselage, and the prop will still turn freely. I'll probably use white glue, so I can pull it all out and fix the thing later, if it falls out again.