Crikey,
Talk about moisture damage!.
Them switches used to be used here in NZ quite prevalently.
5A switching load aren't they?, I have seen some as low as 2A, from back when lighting circuits were rated at 5A a piece.
I see on the switch bodies that they had an English patent, that seems strange when at least one company here made them, but the majority were imported from Good Old Blighty!. [Linked Image]