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Botany Bay

Jim Jones / Good As I Been To You/ 1992

They'll flog the poachin' out of you down there in Botany Bay. (jules n. binoculas):
The way I read it it's pretty clear that he's in New South Wales recounting his trip. He is probably already on land, as how else would he "slip these chains" and "to the bush...go". (Ben Ryan):
(hist.) [in New South Wales, Australia, named from its varied flora and formerly the site of a convict settlement], the destination of a transported convict, transportation. E19.