Since I'm at the point where I'm ready to tear my hair out with this one I thought I'd give it a try in the Co. Down thread. Any help/pointers in the right direction will be VERY gratefully received!
My great great grandfather
William John Sloan was born abt. 1836 and states his county of origin as Down in both the 1901 and 1911 census. He moved to Co. Roscommon circa 1863 when he opened a Hardware store in Main Street, Boyle and subsequently married a local girl, Mary Ann McLean in 1870 in Co. Tyrone (just to confuse things).
On the extract I have of their marriage certificate his father is named as
John Sloan, a farmer and his witness was Thomas K Sloan, who I believe was his brother.
Thomas Knox Sloan died in Boyle, Co. Roscommon in 1881 and his estimated year of birth was 1844, presumably also in Co. Down. One of William John Sloan's children also carried 'Knox' as a middle name in
Margaret Knox Sloan and he had another daughter,
Jessie Scott Sloan whose name doesn't seem to tie in with the McLean line so (hopefully!) might be another tie to the Sloans. William John Sloan died in 1919 in Boyle, Co. Roscommon so no chance of a Will search either. *sigh*
Basically I have absolutely no idea where to go from here. I don't have a townland to narrow it down, the names of his mother or any other siblings to help with the research, and have hit a brick wall which I can't seem to break through, no matter how many angles I try.

So if anyone recognizes any of the names or can give me some advice, I REALLY would appreciate it!
Yours in desperation,
Trish
P.S. Should probably mention that they all appear to be Presbyterian's, not that it's helped me any thus far...