Can anyone explain how you distinguish a b no I from an m mintmark for 1943? The m is no mintmark at all like the P on U.S. money, and if there's no I then there also won't be a mintmark. I don't know how you could tell the difference, but there must be some way.
Melbourne = no mark, Perth = period after "Y" in PENNY, Bombay = period before and after "Y" in Penny
Now this is a question I can answer Perth mintmark is right here Bombay has mintmarks here And here on the bottom of the head So basically you're looking for one that has the double periods with no I on the front.