[5] Millner was appointed Surgeon to the McKinlay party to the Northern Territory, whose brief was to investigate alternative sites for "Palmerston", the proposed new settlement, independent of the work being done by Finniss at Escape Cliffs.

[6] He transferred to the Escape Cliffs settlement party as Surgeon and Protector of Aborigines, replacing Dr Goldsmith, whose resignation Finniss, the Government Resident, had requested and received.

On 22 January 1870, Doctor Millner arrived in Darwin on the barque Kohinoor as Acting Government Resident of the Northern Territory of South Australia.

The following month Doctor Millner, his new wife and the three children of his first marriage (Grace Maude, Esther Eustace and William Sturt) boarded the Gothenburg for Darwin, where he resumed his modified appointment.

On the evening of 24 February 1875, off the north Queensland coast, the Gothenburg hit a section of the Great Barrier Reef near Holbourne Island, during a cyclone.