Robert Geddis and Jane Carter Christchurch Nz

Hello. I am tracing the family history of Robert Geddis and Jane Carter. They married in Christchurch, New Zealand in 1865. Their last born, a daughter named Mabel Jane is my g-g-grandmother. Robert and Jane were born just before the great famine in Ireland 1845-1850 in County Down and County Armagh, respectively.
Am still not sure if they met before or during emigration. Any info would be most appreciated! Blessings..