Hi kvkiwi,
I think this could be them in
1861She's the only Mary Sanders born Kempston I could find, anyway
RG9/990
Folio 83 p. 25
Kempston, Bedfordshire
'Village'
Ann Dudley, head, wid, 66, Pauper (formerly Laundress), b. Bedfordshire Marton
Benjamin Dudley, son, unm, 21, Ag Lab, b. Kempston
Clara Dudley, Granddau, 3, b. do.
Same address or next door:
Henry Sanders, head, 28, Bricklayer, b. do.
Mary, wife, 37, Laundress, b. do.
Sarah A, dau, 1 mth, b. do.
Does the name Sarah A match with what you know?
Tanja