I'd be wondering why you are assuming he was sent to Australia ? That snippet you posted just says, sentenced to transportation, doesn't say where. Thats a problem for the prisons department to solve, not the sentencing judge.
Transportation to NSW ended several years before that, to Tasmania ended about that time, and then started to Perth a little later, and then stopped again. I don't have the dates off the top of my head, and none of my convicts relate to that particular period.
My advice would be to do some research on exactly when actual transportation ended. I'd also check whether there was transportation to anywhere else. What you might find, is that judges kept on for some time issuing sentences of "transportation", after there was no actual place to send people.