10 Shillings Bank of New South Wales

The Bank of New South Wales was the oldest trading bank in Australia, chartered in 1817, and by the 1920s was still issuing its own private banknotes in competition with Commonwealth currency — a situation that would end entirely with the Notes Monopoly Act of 1910's full enforcement pushing private bank notes toward extinction, though trading banks retained rights to issue in limited circumstances for years afterward. The Skipper & East printing in London for antipodean circulation was standard practice for colonial and post-colonial banking institutions that trusted British security printers over locally available alternatives.

The P#S153 designation places this firmly in the private commercial bank series rather than Commonwealth issues — worth noting for anyone cataloging Australian notes by issuing authority.