Hi
In 1851, they're at HO107/2508/291/19 (Llanrwst)
This might be them in 1841 but not sure:
Llandeiniolen, Caernarvonshire
HO107/1394/11/53/21
Hugh Hughes, 40, quarryman
Mary, 30
Robert, 10
John, 6
Mary, 5
Hugh, 3
Charles, 1
None of them were born Caernarvonshire
brevitas