The first piano into the colony did not come on an HMAS anything — that’s a twentieth-century navy prefix — and the surgeon was not Thomas Wargan. George Bouchier Worgan, naval surgeon on HMS Sirius, put a small English square piano in his luggage when the Fleet sailed. Officers heard it at Rio in August 1787; it sat in the camp at Warrane after January 1788. When Worgan went home in 1791 he left it with his pupil Elizabeth Macarthur. She said so herself, in a letter of 7 March 1791: the new house “ornamented with a piano-forte of Mr. Worgan’s,” and under his direction she could get through God Save the King and Foot’s minuet.
That is the Sydney hook — a ship’s surgeon’s instrument in a wattle-and-daub room, not a concert grand on the harbour. Later dealers have hung the story on a Frederick Beck square that turned up in a farm laundry near Windsor in the 1960s. Treat that as a strong identification, not a signed invoice. Don’t baptise a surviving box as “the” First Fleet piano unless a catalogue will say it.