It's possible I've been researching a descendant branch. My 3xg grandfather, James Purvis (
https://www.wikitree.com/wiki/Purvis-2300), was born in Ireland in 1828 and moved to Cumberland, England where he'd married a local girl by 1851, before moving to Hexham, Northumberland, where he died in 1866. The UK census only gives his pob as Ireland, and I think his marriage was a 'border marriage' (so no paperwork), so I don't know where in Ireland he came from. His children's names make clear he was Protestant, and Co Tyrone had the biggest Purvis concentration. I've not managed to make any headway with Irish records, but have had a 23andme DNA test and am thinking of getting the Ancestry test too. Do you have anything about your James's descendants?
Cheers,
Andy