Hi John, This is an interesting one: First the 1861 census that seems to tie everything together.
Long Crendon, Buckinghamshire Joseph Elton Head Wid 39 Butcher Buckinghamshire, Denham George Elton Son 11 Bucks, Long Crendon Ann S. Elton Dau 9 Bucks, Long Crendon Jane Elton Dau 7 Bucks, Long Crendon Charles Elton Son 2 Bucks,Long Crendon Mary Elton Dau 5 Bucks,Long Crendon Jane Eborn Wife's sister 29 Housekeeper Oxford, Waterstock RG9/888 Folio 19 Page 5
Joseph Elton married Jane Eborn during the March Quarter 1862 Thame 3a-625 Joseph Elton married Ann Eborn March Quarter 1849 Thame 16-163 Ann Elton died March Quarter 1861 Thame 3a-367
Here is Jane in 1851 with her family. Waterstock, Oxfordshire Richard Eborn Head Labourer Bucks, Brill Mary Eborn Wife 61 Oxford, Waterstock George eborn Son 28 Gamekeper Oxon, Waterstock Joseph Eborn Son 22 Labourer Oxon, Waterstock Jane Eborn Dau 19 Oxon, Waterstock John Eborn Saon 14 Oxon, Waterstock HO107/1726 Folio 538 Page 6.
I can't find Joseph Elton with his family but did find a Joseph who might be his father - a butcher in Denham, Bucks in 1841 with a wife named Charlotte. Joseph 50 - Charlotte 55.