Well thank you to everyone who voted! Colour 1 is the clear winner so unless anyone has any objections, this is the one to use for RAN ships
(though I'm not sure when it was first used...my guess would be sometime in the late 60's or early 70's)
I've drawn up a colour chart to help:
Note: The black underwater hull is not universal for all RAN vessels, as many ships use/used red.