Brass wings similar to the badge shown above were indeed approved in 1956 for wear on No 3 Dress (Warm Weather Ceremonial). It was intended for wear on the white linen tunic, which looks like the No 1 Dress tunic, along with other detachable insignia and buttons allowing for frequent laundering. The Australian wing from the 1990s is similar in appearance and clearly inspired by the British design but not quite the same and has US-style clutch fixings rather than the British loops for the split-pin.
Tom