Looking back over this info I do not think that Llewellyn is Ward's dad, I think it could be wife Elizabeth father, this fits with 1841 info - there is only one Ward on the 1841 right age area and a smith his father is Jenkin David, also the name of one son on the 1871 also the marriage details below confirm the possibility, but getting the cert would prove it
Marriages Mar 1847
David Elizabeth Bridgend 26 391
David Ward Bridgend 26 391
Do you want to post details for Ward and father?
Cas