Thanks for all the interest. According to the details I found on the High Littleton Parish registers William and Ann had 5 children. Maria, James, Jesse, Abel and Hannah. James and Jesse moved to the Midlands where they worked as miners. James married a local girl but Jesse married a girl from Somerset although they didn't get married until they moved to the Midlands. I did find one Symes on these registers. A Thomas Symes who was living in High Littleton who married a Mary Ashman in Paulton, in 1762, however these would seem more likely to be grandparents. I wonder whether Ann Symes was born in Paulton ?
Jenny