Correct Luke..... Mr Marsh 1970s.
You can also find them in silver and hallmarked.... I think the last one I saw was by Gordon Brindley..... so he obviously got hold of the die (or was given/purchased a batch of silver versions). You can find them in brass, white metal, bronzed... all sorts.
You will find them on old uniform.... because they have been put there in modern times.
If you want to see the real Arm Badges then see here :-
https://www.paoyeomanry.org.uk/Motto/NCOArmMotto.htm