Hagan or O'Hagan

Looking for records or descendants of Stephen and Mary Hagan (need Shiels) from Clonduff parish, County Down.  I know he farmed plot 28 on the corner of Cabra Road and Islandmoyle Road in the 1800s. Two of their sons, Michael and Charles (O'Hagan) settled in New  Zealand around 1865 after first working in the goldfields of Australia. I have a copy of a baptism certificate for Michael (dated 1835) which he got from Father Kearns around 1914 on one of his many trips back home. Also have a photograph of a memorial headstone for a sister, Susannah. I have visited the church and found parish records no longer exist for around 1835. 

ANy information would be much appreciated.