I've currently got a Cornelius Bartlett of Wells in my sights as the father of George Bartlett(1796) and who was married to Charlotte. There was another son Cornelius jnr. b.1803 and quite possibly another, Abraham b.1808. George and Cornelius jnr. were shoemakers and Abraham a tailor. I have noted that there is a newspaper record of the death of Cornelius Bartlett aged 87 in Wells in 1851 which must be your ancestor.So before I proceed further, do you know if your Cornelius had other children and the name of Joseph's mother?