I have a couple of photo's, but will have to drop the base-plate off the block to double-check which axle.
I am 90% sure I have swapped these in the past, but it is a few years ago now..
I have 'lost' some of my spares, in the move..
I have found some (all helical-cut) and the box of removed, worn gears)..
Thanks for the information.
PhilP