Hello
I've checked that baptism for Sarah Stephens and I think you are right .It looks like her brother Richard is buried at Sarnefield born c 1735 which would fit with a baptism to Richard and Jane in 11 Sep 1736 at Mansell Lacey.Gravestone 29 Jan 1795 age 59 years.
www.findagrave.com/memorial/126489918/richard-stephens.
Samuel Ferrar left a Will 3.5.1809 at Hereford Archives ,£800 of Sarnefield Executor Sarah.Burial 8th March. Plaque at Winforton says died 6th ,born 1725 and another wife Eleanor Price Ferrar 1723-1777.There is a possible first marriage to an Eleanor Price at St Martins in the Fields 23 Dec 1753.
www.findagrave.com/memorial/199392738/samuel-ferrarSamuel and Sarah's son Benjamin's may be Winforton 1799 ,£100 to Exec Samuel Ferrar but no sign of a burial.
Also an Admin for John Ferrar of Winforton 3.3.1803 to brother Samuel and granddaughter Elizabeth Burnham ,£300. Burial 26 Dec 1802 ?
John bapt 30 July 1715 s of Thomas and Anne Winforton and Samuel 28 Feb 1725
Hope that helps
Sorry forgot to add Sarah Ferror age 88 buried Norton Canon 13.11.1829 which adds a bit to her age but I am sure is her.
Ciderdrinker