Steven,
Thanks for that information. I found the marriage record of Sampson Jervois and Frances O’Hea on the http://www.irishgenealogy.ie website in the Roman Catholic marriages for West Cork.Both listed as RC.So it would appear that there is also a RC branch of the Jervois family
I know that according to manuscripts held in National Library on the O’Hea family that John O’Heas family were Protestant and according to these manuscripts Martha’s father was a Major?. However, 2 of John and Martha’s children, John who was my great great grandfather married Honoria Deasy who was Catholic in 1826 while his brother James also married into a Catholic family (Alice White in 1838), Neither brother had any objections to their children been reared as RCs
Again, thanks