Kate, No I don't think it is the right couple, because "mine" were well settled in Tamworth. Thomas was supposed to be a sulky driver for a local Dr, as well as running a farm at Nemingha on the outskirts of Tamworth, where Farrer Agricultural College is now. Catherine was acting as a midwife. Gosford would not be where she would go to have a baby.
What I now feel may have happened, centres around Thomas' brother Richard.
Richard was born 1841 and married Margaret Hogue Jeffrey in 1867. Children: Richard born 1867, Alison 1869, Laura 1872, James M 1874 and George 1876. Richard unexpectedly died 16/7/1877, he was a farmer on the Cockburn River at Nemingha outside Tamworth. This is around the time that Thomas and family came to Tamworth, whether because of this I am not sure. We know that Thomas and Catherine had a son Richard in Tamworth in 1878, pretty obviously named after his just deceased uncle. Margaret Greentree (widow) married Henry Hunt in Tamworth in 1878 .. Sarah born 1879, Henry John R Jnr born 1880 and Georgina M born 1882 at Tamworth .. there is also a Mary born 1892 at Wilcannia, but not sure it is the right Henry and Margaret Hunt as parents. I am wondering now if the two small Greentree boys, James and George, morphed into sons of Thomas, as Richard was dead? They certainly wouldn't have remembered their birth father and may not have been very welcome by their step father. This is only supposition of course .. Thanks for your interest Kate .. I am sure flying blind here ..