In the 1841 Census there is a residence called Gwyndy Bach, apparently an "out building" on the farm Gwyndy. It is located in Llandrygarn. Residents include: Hugh Owen 25, Owen Williams 45, Elizabeth Williams 45, William Owen 25, Elizabeth Williams 12 , John Williams 55, Elizabeth Williams 55, Owen Williams 20.
It appears to be a very large farm, including several out buildings with a second one also named Gwyndy Bach. This second building in inhabited by Thomas and Rowland families.
It'll take someone better than I at figuring out census records to straighten this out. Hope it helps.
Richard Owens