Part of what you write appears to fit in with my family tree although other parts do not.My g.g.grandfather was Robert Diffin and his wife was Rosanna Turner. They were married about 1824/6.Robert was born in 1792 and Rosanna in 1805.Robert died 19/12/1873 and Rosanna 19/5/1859.Robert had at least 9 siblings two of whom went to Canada and eventually settled in Maine. Between them they had 20 children and their descendants are still in that area.
Children of another brother went to Australia and New Zealand.They did not change their name to Devine.I have no record of a Mary Ann or a Margaret born to Robert and Rosanna but it is possible.There was a Rose Ann born on 28/2/1845.she died 25/3/1888 in Queensland.
Robert's eldest son John went to Australia in 1874 with his wife Sarah Carson and 9 children.The eldest child Margaret was born on 5/8/1854.John was joining brother William Robert and sister Martha who went to Australia in 1863.These two changed their names to Devine when they arrived in Australia and John followed this when he arrived.
Could I use e-mail for any future correspondence.My e-mail is email@example.com