Hi Andrew
The following is the closest I can see to your info...
Source, IGI (submitted):
Thomas Vincent b. 22 Oct 1739, b. 7 Dec 1739, Sudbury. Parents, Joseph Vincent & Susannah.
No sign of William with same parents as you suggest.
Source, IGI Family Group (submitted):
Mr & Mrs Vincent
Children:
William, b. abt 1736, Bury St Edmonds, d. 1801*.
Thomas, b. abt 1738, Bury St Edmonds.
Source, NBI*:
18 Sept 1801, William Vincent aged 58, Bury St Edmonds, bur.
There are some variations in dates; because some of the info is submitted, it is open to error.
Regards
Geoff