Hi Steve
This looks like your family:
1851 living at Canal Rd, Llanllwchaiairn
David Morgan (46) Timber merchant b. Kerry
Susanna Morgan (48) wife, b. Newtown
Susanna Morgan (17) daughter, b. Llanllwchaiarn
Charles Morgan (15) son, b. Llanllwchaiarn
Harriet Morgan (11) daughter, b. Llanllwchaiarn
1861 living at Canal Cottage, Llanllwchaiarn
David Morgan (56) agent Shrop Union R.D.C., b. Kerry
Susanna Morgan (58) wife, b. Welshpool ??
Harriet A. Morgan (20) daughter, b. Llanllwchaiarn
Catherine Alma Ash (5) granddaughter, b. Portmadoc, Caernarfonshire
plus 1 servant.
Hope this helps
Regards
Stan (Brynhyfryd)