Hello Walmer
I'm still trying to get things straight: bear with me.
Your ancestor is a Sarah Maggs, child of a George, right?
The Somerset family (mentioned by Mabel) with a Sarah, daughter of a George is the one in West Harptree baptising (in West Harptree) Ann & Hester in 1815, Thomas in 1817, Sarah in 1820, Mary in 1823 and Maria in 1827.
There is however a Sarah born to a George and Leah baptised in Midsomer Norton in 1809 - this could tie in with the George baptised in Ashwick 1800.
However: The family in West Harptree called their first daughter Ann and their first son Thomas. If their father George is the baptism recorded in 1794 in Midsomer Norton then his parents were Thomas and Ann - a likely naming pattern can be seen.
Do you know for certain that your ancestor Sarah was born in 1820 (and that therefore her father George would seem to have married an Elizabeth). Perhaps you already knew the names of her siblings?
Or could she possibly be the one born eleven years earlier to George and Leah, also in Midsomer Norton?
By the way, I think people travelled a lot more than we think they did. My ancestors were non-conformists in 18th century Somerset and baptised their children, if they could, in presbyterian churches 3 and 5 miles away - rather than in their own village with a potentially absentee Anglican rector/vicar .
Have you found Sarah on a census? Was she married by 1841?