Re "pom"

My mate Kevin, from Adelaide, told me pohm (his spelling) comes from Prisoner Of Her Majesty, which was stenciled on convicts clothes as Sugwash says. True or not (and Kevin is a spectacular liar), I like this explanation because of the subtle twist built into it: once Australia set up shop as an independent nation, they could laugh at the Brits who were, still, Prisoners Of Her Majesty.

Jerry