Susannah Kingwell was baptised 15 May 1774 at St Ewe, Cornwall. I looked at her family, wondering if Thomas and Sarah could have been my Thomas Kingwell's parents.
Most of the Kingswells were located in Hampshire and on the Isle of Wight in the 1800s. The spelling Kingwell (and in some areas, Kingwill) was prevalent in Devon and Cornwall at that time. Before then, you could spell a name however you wished; you didn't have to keep to the same form?