> Is this US product [Kroil], in UK terms, WD40, does anyone know?

In the US we have _both_ Kroil and WD-40.  They certainly are different
brands (marques).

I think Kroil is sold in much larger containers than the little can
(or spray can) in which one usually sees WD-40 and it is typically sold
through the mail (post).

I have never actually had any contact with Kroil, but I seem to recall
a colleague (an engineering professor and part-time farmer) speaking
highly of it.

Wallace Venable