Designed by George Gilbert Scott for a branch of the Fussell family who had works here a couple of miles from Mells. I only had 10minutes, but quick snaps confirm it as a very original work despite 'gothic revival' slot well worth the Grade 1 listing. Maybe more the work of his junior partner William Bonython Moffatt or anyway has a lighter touch than GGS's later and larger buildings.
http://www.britishlistedbuildings.co.uk/en-266897-church-of-the-holy-trinity-whatley