Thanks. The Halkey Roberts bit was the missing link (not mentioned in the advert). Once you see a Halkey Roberts valve, its obvious how this fits, but my Zodiac doesn't have them so alas, they are of no use.
It would be really good if there was one that could be made to take the place of the reducing cylinder valve adaptor
needed for the later Cadet/Fastroller recessed flush valves.
FYI, on a Zodiac Fastroller, the floor is the first thing to be inflated. Full pressure followed by the tubes. So as you go to inflate the tubes, the pump is at >11psi unless someone turns it down... hence I don't let others inflate.