Two videos on the subject. If the first I make some progress with a file but no joy.
In the second I manage to get a bit more movement and finish off the process by running the gears with valve lapping compound. AKA lapped the gears. This one may still be uploading.
This afternoon. I ran all the parts I had been working on through the parts washer and coated then machined surfaces with WD40. For some reason they don't look clean in the picture.
There is still some fitting to do to make it right but its on the way.
Thanks to everyone who made suggestion. Even ones that don't work out help in that they get the juices flowing.