For the benefit of those who have not seen the Australian and New Zealand plugs, I have illustrated some examples below. They are also used in Argentina, slightly modified to take a thin pair of round pins (an alternate plug) in the pair of inclined slots. Note also the silver earth (grounding) pin of the bottom plug is stamped "GREEN". Dabs of brown and blue paint (the colors of the live and neutral wires) are present near the compression screws of the other pins.

[Linked Image from elkonv.com]

Interesting question you raise Paul about the use of the old round pin plugs in the Dominions. I wonder what India used and what it uses now.