In the 1881 census in the caravan next to Eliza Roberts and Tom Goldsmith in Cowper Road, Sittingbourne are William Stone head, 57, no birthplace given, Mary wife, 53, b. Cranbrook, Albert 15, Romford, Cecilia 12, Chilham (maybe the Celia who m. Thomas Johnson whose sister Deborah married Moses, Tom Goldmith's brother.
In that 1861 census William is 26 which should perhaps be 36 as his son Stephen is 15. Then this family would fit with the 1881 Stone family.
I have seen Enumerators' Books and the writing sometimes is so bad that a 3 could easily be transcribed as 2.
Best wishes,
Brenda