+1 for what old mart says.
In later years Beaver mills were fitted with simple plate handles with an ordinary rotating handgrip screwed on. Less than posh but effective and no one in their right mind would quibble about the overall quality and capability of a Beaver.
Your broken die cast handle looks like the ones on my cross vice. Fit is less than wonderful, finish poor and everything wobble'n wobbles. If I ever break mine they are getting replaced with something nicer.
Clive