Thanks JM for all the leads.
Yes I have the 1865 marriage certificate - Christian Kilpatrick married George Norman in Sandridge (now Port Melbourne), father named as James Crombie Kilptarick, mother Mary O'Connor.
Yes also have the birth certificate and James did register the birth in 1855 in Sandridge.
So my best guess of his movements is 1850 left Manchester, arrived Port Adelaide Jan 1851. Stayed in Adelaide until 1853-54 then moved to Sandridge, Victoria before 1855.
The family seems to have stayed in Sandridge until Mary's death in 1892. She is named as relict of James Crombie Kilpatrick in the death announcements in the paper and her death certificate also says widow. I have therefore been focusing on pre 1892, but always possible the family gave this info if Mary was abandoned. I'll have to check the Avoca one again. I did download all the Vic ones that looked vaguely close and all had major differences to my info. Had not seen the SA one.
Thanks
Sue