I may be clutching at straws here but looked at Timothy/Ann Hale* who Mary was with in 1841 Census.
Timothy HALL died 1842 age 65, buried 26 Aug 1842 ( born c 1777)
Married Ann PALMER 1798 Claybrooke
Children bapt Claybrooke to them;
THOMAS 1802 born 1802
RICHARD 1805, born 1804, buried 1806
SARAH 30 March 1810 born 19 Oct 1809*****
ANNE 1813 born 1812
RICHARD 1823
Large gap in children 1812-1822
Is it possible Sarah 1809 married a John Wilford and therefore Timothy/Ann are Mary Wilfords Grandparents?
Just a theory to explore more.