Graveyards

I was reading the Whitby family book of old wills and in the front page if mentions a Mary Whitby who died in 1820. The only Mary Whitby currently in tree is Mary Whitby (nee Toombs) but it can't be her as she died after 1883. It says that Mary Whitby (d.aft.1820) was buried in Ewell Churchyard, Surrey. I called them up and they've kindly said they'll post some details.