As an alternative option,as he is referred to as Henry Roberts jnr at one stage,is it not likely his father was called Henry Roberts,and though the location is a litttle more distant there is
Henry Roberts - Llanbedr - born 04/11/1815,christened 12/11/1815 to Henry Roberts and Margaret Davies(Henry "jnr" names a daughter Margaret)
I assume the LLanbedr is Llanbedr y cennin?
Regards
Roger