Thomas Robertson (II) was born in Glenmuick, Aberdeenshire (baptised on 5th April 1824), the youngest of the five children of Thomas Robertson (1785-1872) and his wife Anne (née Lachlan). The other children were Jane (Jean) (1816-1895); James (1818-1893); Margaret (1820-1909); and John (1822-1905). Each of them married and had 7, 10, 9, and 7 children respectively. Eight of these thirty-eight died before they reached the age of 20.
In 1839 the Robertsons emigrated to Australia. The elder Thomas took with him his children (his son Thomas was then fifteen) and the six children of his deceased sister Mary Gordon (the youngest was 11 years old). The Robertson family had been Presbyterians in Scotland, and when they got to Australia they seem to have married other Scots, probably also Presbyterians.
Soon after Thomas' father died (June 1872) the family firm split up, and Thomas purchased a large sheep station, Brewarranna, in New South Wales, sold it a few years later and purchased a sheep station called Toganmain, with an area of 167,000 acres, which was very roughly in the shape of a rectangle on the Southern side of the Murrumbidgee River; it had about 13 miles of river on its northern side. In 1905 they had 100,000 sheep there. The station remained in Robertson hands until 1988, when John Robertson sold it. (He is the son of Graham, shot down in 1942 at the age of twenty-eight, and the grandson of Thomas' son John Seymour Robertson).
Grace Dickson (1879-1945), was the youngest daughter of Thomas Robertson (1824-1904) and his wife Grace (née Duncan). Their other children were a son, Duncan, who died aged 11 months (birthday unknown); Margaret Maud Isobel (b.1875, m. Robin Johnson); Anne Caroline (b. 1877, died unmarried between the wars); and John Seymour (b.1882, m. 1907 Constance Bettington). (I have another source that refers to Miss Bettington as Beatrix, the youngest daughter of Mr. J.B.Bettington, of Brindley park, new South Wales. The discrepancy is explained by her sons memorial, where she is named as Constance Beatrix Robertson.)
However Thomas died (10/3/1904) at another property: Merioola, Edgecliff Road, Woollahra, Sydney. This was a vast mansion in substantial grounds. It has an interesting history but no longer exists. I am not sure which part of Sydney this was - Greater Sydney is very large now. There is a fairly long road of this name in Double Bay, an expensive area on the southern side of the harbour and east of the city centre. One of Thomas's Johnson descendants ran an antique shop in Double Bay.