It is unlikely that Mary Ann Gosper married/had a relationship with John Heaton/Eaton who died in Queensland in 1904. His death certificate says that he married Mary Ann Onus in 1831. This is confirmed by the NSW BDM index. Mary Ann Onus remained his wife.
'Sanders, Mary Ann (1823–1880)', People Australia, National Centre of Biography, Australian National University, https://peopleaustralia.anu.edu.au/biography/sanders-mary-ann-24440/text33167, accessed 14 October 2024.
16 February,
1823
Freeman's Reach,
New South Wales,
Australia
11 April,
1880
(aged 57)
Lower Portland,
New South Wales,
Australia