I am looking for information on

Helen Eaglesham, born 1820 Ballochneil, Kirkoswald, Ayrshire. Father Robert Eaglesham, mother Helen Niven. Died 1891 Christchurch, New Zealand.

She married Douglas Graham in 1857, possibly in Springbank, New Zealand. He was born 1817 and died 1872, Christchurch, New Zealand.

I do not know if they had any children, and I don't know anything about Douglas' family.

Any information on these people, or the history of Christchurch would be great!
Thank you