Sometimes in these cases it is fruitful to cast the net wider. Trigg is not a common name. I think there were Trigg's at Westbury on Severn (Elton?).

Marriage 4Aug1807 W on S No 289. Thomas Evans born c1781, farmer, and Margaret Trigg born c1787. Both literate, She signed herself Margaretta. Children include a John and an Edwin. OK John is unremarkable but Edwin was rare. These people may have been wider family of what you are looking for.

Good Luck,

Roger