Thanks for that, Snowballz. I somehow missed your post last year; I hope you're finding RootsChat helpful.
Sir Edwin Windsor Bayntun-Sandys was the only surviving brother of my ancestress, and died before his father so that the baronet title became extinct. He was rector of Winstone near Cirencester.
Mary Ann, née Turner, was his wife. Cambridge Street is in Belgravia; that's where she died, but I assume was buried at Miserden if she's in the parish register.
Sarah Harriet was a sister, baptized in 1817 as (I think) Harriet Sarah; I knew she'd died before 1837, but didn't know when or where.
That's exciting news, Descendant of Murby. Would you be prepared to photograph the Sandys Reed stone or stones, if possible so that the inscriptions show up clearly? I don't think one can attach images to a personal message, but if you let me know that you have a photo or photos I can tell you my eMail address.