I decided to see how the bearing mod was working out and stripped it down.
It's only had a few weeks use and as you can see this new shaft has considerable wear.
I had given it a light polish before fitting it, I don't think I will have removed any case hardening, if any was used. The end of this shaft just seems too soft for metal to metal contact. The oil I used may have been too thin, but I don't think it will have been a major factor. DO NOT RUN THIS SHAFT ON A STEEL THRUST PLATE.
I cleaned up the shaft and replaced the metal shim with an original plastic item and increased the oil viscosity to straight SAE 20.