I note that Sarah Agnes Selsby married Thomas Jennings, both of Cuckfield, on July 16th 1881.
And that Mary Ann Selsby married George Frederick Ruewell, both of Cuckfield, on May 1st 1880. And, strangely on that same Mayday, Warden Henry Starley also married Alice Gryner (other spellings occur) and one of my grandfathers was called Warden Selsby. That Christian name must have been more common a century ago, but to find a Warden and a Selsby getting married on the same (May)day at the same rural location seems intriguing. Especially if your grandfather is called Warden Selsby.