Thomas Tothill and Sarah (Née Kellan) had a daughter Sarah Tothill, who was Christened in 1740. It is speculated (on another website) that Thomas Tothill died (there is a burial of a Thomas Tothill at Thorverton in 1742), that Sarah senior then married Simon Summers and so the daughter's name was changed to Sarah Tothill Summers. I am still searching for a marriage entry in the parish registers to confirm this.