Mk3 Kickstarter

Has anyone put a Mk3 kickstarter onto an older model?

I have bought one at great expense but the splines on the new lever do not extend all the way around. It will not slide onto the kickstart shaft.

Before I start removing metal I am interested if there are any forum experiences.

I have MkIII kickers on all of my Commandos. I don't recall any problems mounting them. The kickstart shafts are the same. If this is a new part, I would seriously consider returning it.