Hi Sue,
South Australian deaths before 1900 do not give years in Australia. I believe she came to SA in 1847 on the ship Dorset via Sydney. The only details on the marriage certificate are age and the names of witnesses which were Emma Blackie and Agnes Davidson. There is also a discrepancy on the death details, age given in 1879 on the death cert is 51, age on the burial register for the cemetery is 57. Husband John also upped and downed his age, we think because she was older. I had thought if Robert Corkill had a sister Mary Ann then it would be a reasonable assumption that they were siblings. I know it sounds pretty useless but that is all I have. Thanks
Robin