I have just installed the upgrade kit and on running the machine for the first time was disappointed to find that I could not undo the EzyLock nut (the name is something of a hostage to fortune).
I am grateful therefore to the posters above for pointing out the correct, counter-intuitive, technique of grasping the wheel rather than the nut. I did also check the Alan Holtham video and, belatedly, the instructions supplied with the upgrade kit and the problem was solved for the moment at least.
By the way, the nut is not only LH thread but also twin-start, a fact I discovered when looking into making my own.
AH did not deal with the replacement bearings: they seemed rather loose on the spindle but I think they may have closed up a little on being tapped into place and are now a snug fit.