I have an old cylinder that is in test ... it has an A Clamp valve fitted.
When it is next in for test I would like to have the valve changed to an MDE
type (A-clamp/DIN)

I know there are 2 types of thread .. DIN 477-6  or EN144-1    ....... is
there a way to tell which the cylinder has without taking the valve out ?

Are MDE type valves available for both types of cylinder threads ?

I had a friend drop my cylinder in for a fill last week and he asked at the
shop ... but the answer was , "it won't take a DIN valve as the valve does
not have the insert"???     which I think they misunderstood the question,
that answer would probably mean they were thinking of fitting a DIN 1st
stage to this existing cylinder valve.

(which of course you can't)