Long shot but could this be any earlier child of George & Susannah???
(Would mean the wedding was before 1800 not 1804

)
Name: Thomas Osmond
Gender: Male
Christening Date: 02 Mar 1800
Christening Place: SAINT PAUL COVENT GARDEN,WESTMINSTER,LONDON,ENGLAND
Birth Date: 27 Jan 1800
Father's Name: George Osmond
Mother's Name: Susannah Merchant