Light Switch Cover with key hook for standard Australian wall plate.
Common wall plate cover Clipsal No. 2000 - wall plate cover will be the same no matter how many switches. (standard cover should pull off easily to check)
Dimensions for hook insert in images if you want to model your own insert.

Print instructions

Print with front of wall plate cover facing down.
No supports required.
Insert hook in to the dove-tail join on the rear of wall plate cover.
Cover is press fit on to wall plate.