I'm sure I have read somewhere that these words were indeed put together by Lloyd and that they embody an anachronism. I can't immediately find the reference and I'm not sure of the details, but I think it was that the penal settlement on Cockatoo Hill closed some time before the particular gold diggings mentioned were in operation. The suggestion was that this was a Lloyd conscious rebuild of another song (possibly The Murrimbidgee Shearer, I don't remember).