In message , "Dave Plowman (News)"
writes
But if it's a sort of circlip isn't it made out of some form of spring
steel?

No, it only turned into a circlip in your first reply I just asked
about this "U-shaped clip"

It might actually need to be moderately springy to absorb the shocks
(and perhaps occasional verbal threats) when working against time, but I
suspect that if box section works at all, I'll cobble up enough spares.

I am grateful for all the replies. I just need to wait till my
mother-of-all-colds passes and I can get something done again.
--
Bill