If this marriage entry from FreeDMB
Dec 1839
ELLIS, Ann, Cuckfield, 7, 471ELLIS, James, Cuckfield, 7, 471
Ford, Lydia, Cuckfield, 7, 471
Harding, John, Cuckfield, 7, 471
HEADO_, William Henry, Cuckfield, 7, 471
SHILSON, Minerva, Cuckfield, 7, 471
SELSBY, Charles, Cuckfield, 7, 471 FreeDMB have a note about this being a mis-spelling.
SILSBY, Charles, Cuckfield, 7, 471STONER, Eliza, Cuckfield, 7, 471
refers to this census entry from FreeCen
1861
Piece: RG9/583 Place: Hurstpierpoint -Sussex Enumeration District: 11
Civil Parish: Twineham Ecclesiastical Parish: -
Folio: 154 Page: 2 Schedule: 7
Address: Mercers
SILSBY Charles Head M M 74 Ag Lab Sussex - Shermanbury
SILSBY Ann Wife M F 69 Sussex - Cowfold
SILSBY James Son U M 24 Ag Lab Sussex - Woodmancote
Then either James' age is wrong or he was born out of wedlock.

Currently investigating the Hillmans of Sussex.