Jamjar, in Reply #8 I transcribed some information from the Carcoar cemetery record on the Australian Cemetery Index which gives information about Margaret AUSTIN, who may be the daughter-in-law of the older John Austin.
Information on the Australian Cemetery Index is often compiled by local historians who have knowledge of the families. Obviously it needs to be reconciled with certificates to be absolutely sure.
Margaret AUSTIN, d 15.6.1898, aged 66 years (thus b abt 1835)
[Dau of John WINTERBOTTOM and Rosanna SPENCER, M John AUSTIN
Carcoar, Died Carcoar
Bur C of E Carcoar]
A small obit from the National Advocate (Bathurst) shows that AUSTIN was this lady's married name.
https://trove.nla.gov.au/newspaper/article/156740432Edit to add - the passenger list for the Honduras, arr June 1839
(New South Wales, Australia, Unassisted Immigrant Passenger Lists, 1826-1922) definitely shows
John AUSTIN, wife and 8 children (no names for wife and children) on the list
Judith