I have an old kitchen tap and when I removed the protective cover I saw the body of the valve (I think !).
It had a sort of nut on its upper surface which I measured with a pair of sliding calipers as being 13/16 inch across the flats of the nut.
What size spanner in old UK measurements is normally used to fit this?
What size spanner (in current mm) is a good fit for this, if there a modern size which fits well?