My gg grandmother Elizabeth Bonner was born in Carmarthen in 1817 and the daughter of John Bona b 1772 and Elizabeth Jones b 1774(her baptism was in the name of Bona).She then moves to Merthyr Tydfil where she marries my gg grandfather John Davies in 1840. It is on their marriage certificate that her name is spelled Bonner.
Her father John was down as a carpenter on the marriage certificate and there is a John Bonner aged 30, also a carpenter,who I think could be Elizabeth's brother,living near Langynidr Brecon in 1841.This is only about 10 to 12 miles from Merthyr Tydfil.