Cavantreeduff is just north of the townlands of Cleggan and Mullycovet between Letterbreen and Belcoo Co. Fermanagh, on a road that parallels the Sligo Road (A4) from Enniskillen. In modern terms roughly 54*18'49" N, 7*49'19" W in GiggleEarth. In the Ask About Ireland site, go to Griffiths valuation, then enter Cavantreeduff and it will show a line with "Occupants" and "Map View".
My great great grandfolks, Thomas MAGUIRE and Lucy PATTERSON lived in Cleggan and were married in 1820 in the closest C of I church at Mullaghdun about a mile east. There are Pattersons in the graveyard there, but I don't see any Roberts. There is a Catholic church between the Mullaghdun church and the A4, but I don't know its name. There were more Pattersons in the nearby townlands of Drumawillan in 1835, Drumconlan in 1825, Dornogagh in 1829, and Cleggan in 1845.
Good luck. I'll see if I can get to you by private message.