Hello Marc
the 1881 census RG11 Piece number 5585 Folio 74 Page 9
has Owen Thomas, a farm bailiff living with his wife Mary, daughters Elizabeth and Ann, and grandson Owen. The property is transcribed as Lamdda Fawr, but looking at the image for the census it is clear the "G" has been mistaken for an "L".
Going back ten years to the 1871 census, the same family is living there, Owen, wife Mary, daughter Elizabeth (no sister Ann, but one called Margrad).
Going back to 1861, still at the same property, Owen is a joiner, but wife is listed as Marged and daughters Mary, Elin, Ann, Elizabeth and Margrad.
Going back to 1851, the family are still at Gamdda Fawr. Owen is a joiner born 1815, Mary his wife is a milliner born 1817, and children Mary born 1847 and Elinor born 1849. Just above Owen and his family on the 1851 census image is another family listed as residing at Gamdda Fawr (not sure if this means the property was divided into two?), a man also called Owen Thomas a stonemason born 1771, his wife Eleanor born 1771 and a grandson called Owen born 1840
hope this helps you start your search
Mar