I think this would be your family:
https://familysearch.org/searchJohn BONNET Christening: 6 January 1833, St. Marys, Ely, Cambridge, England
William BONNETChristening: 6 January 1833, St. Marys, Ely, Cambridge, England
Robert BONNETChristening: 1 November 1835, St. Marys, Ely, Cambridge, England
Ann BONNETChristening: 8 April 1838, St Marys, Ely, Cambridge, England
All the above with parents John and Catherine.
1841
Well Horn?
Emneth, NorfolkClass: HO107; Piece: 770 Folio: 12; Page: 17
John BONNETT/BENNETT, 30, Ag. Lab., not born in County
Catherine, 30, born in County
John, 9, born in County
William, 7, born in County
Robert, 5, not born in County
Mary, 4, not born in County
Despite the names and ages, is this them in 1851?
1851
Newnham Street
Holy Trinity, ElyClass: HO107; Piece: 1764; Folio: 313; Page: 29
Charlett BONNETT/BENNETT, Head, 55, M(arried)?, born Terington, Norfolk
Ann, dau., 8, born Ely, Cambridgeshire
John, 21, Ag. Lab, born Ely, Cambridgeshire
Robert, 10, Ag. Lab, born Ely, Cambridgeshire
William, 4, born Ely, Cambridgeshire
Allice HOWELL or HEWELL, Lodger, W(idowed), 65, born Ely, Cambridgeshire
All children unmarried
1861 Census for Holy Trinity, Ely is missing 1871
Newnham Street
Holy Trinity, ElyCatherine BONNETT, Head, Mar, 62, born Terrington, Lincolnshire
Robert, Son, Unm., 27, Labourer, born Ely, Cambridgeshire
Ann CROSS(?), Dau, W, 25, born Ely, Cambridgeshire
James BONNETT, Grandson, 7, born Ely, Cambridgeshire
Walter CROSS, Grandson, 3, born Ely, Cambridgeshire
Elizabeth CROSS, Grandau, 10 months, born Ely, Cambridgeshire
Catherine says she is 'married' but John has been missing since 1841-1851. Hmm, I think he may have gone on an all expenses paid cruise
John BONNETT
Age: 39
Tried: 6 Jan 1847
Isle of Ely Sessions, Cambridgeshire, England
Sheep Stealing
Sentence: 10 years TransportationDebra