Could James Whitworth and Elizabeth Marsh have had children die in infancy between 1821 and 1829.Then they could have had Grace and Thomas who survived.Then perhaps Elizabeth died and James remarried to Elizabeth Whitworth in 1841 and then had James Whitworth and Emily, Samuel, Ernest and Clement.??
Check the IGI by putting in James Whitworth and Elizabeth as parents and see if there are any records of more childrens deaths or baptisms. Also check to find a death of the first Elizabeth.
Elizabeth may have inserted her last name after James to preserve it. It may also have been her mothers maiden name or James Fraser's mothers maiden name.