Searching for Irish roots around 1826

I've been trying to find any Irish history of my grt grt grandparents who lived in Down (I believe) and who travelled to Carlisle, Cumberland about 1848 or thereabouts.

My grt grt grandfather'so name was John Duffy who was born around 1826 and my grt grt grandmother's name was Catherine McGlade, born about the same time. I'm not sure if this is the right parish or not?

If there is anyone who has access to birth or marriage records there, please could you let me know?  They had 2 children born in Ireland in around 1844  by the names of Henry and John.

Thank you.

Jan Webb