Hi David, Annette has given you most of what I have on the immediate family, though I can clarify the marriage date of William SENNITT and Alice JACKSON as being 7 february 1832 at Stretham, Cambridgeshire.
I can also take the SENNITT line back considerably further: William was christened 28 Apr 1805 at Stretham, and buried 4 feb 1880, also at Stretham. Alice was born abt 1805 in Cambridgeshire, and was buried 2 mar 1865 at Stretham. William was the son of William SENNITT and Mary LOE/LOWE (married 8 oct 1798 at Stretham - Mary was Williams second, of three, wives). William was christened 8 aug 1773 in Stretham, and buried 1 feb 1853 in Stretham. Mary (Loe/Lowe) was buried 14 apr 1812 in Stretham. William (senior) was the son of John SENNITT and Jane HITCH. John was born about 1743 and buried 14 oct 1798 in Stretham. Jane (Hitch) was burned 29 jan 1781 in Stretham. John and Jane HITCH married 11 jul 1768 in Stretham. I believe John to be the son of John SENNITT and Elizabeth WOODLAND who were married 22 March 1741 at Cambridge St Edward, Cambridgeshire. John (senior) was christened 31 aug 1719 at Stretham and buried 27 May 1792. He was the son of Francis SENNITT (1685-1738) and Damaris READE (died 1738). Francis was christened 31 jan 1685 at Cottenham, Cambridgeshire to parents John SENNITT and Susanna FULLSTONE, who were married 31 mar 1681 at Cambridge St Edwards. John was christened 24 mar 1660 at Cottenham to parents Arthur SENNITT and Susan FOREMAN, who were married 18 apr 1660 at Cottenham. Arthur died 30 may 1710 and was buried 1 jun 1710 at Cottenham. I believe Arthur to be the son of Thomas SEINNET (chr 21 mar 1590, Cottenham and buried 15 nov 1661, Cottenham) and his wife Elizabeth. Thomas is probably a son of Bartholomew SENETT who was buried 4 feb 1592 at Cottenham All Saints. This information has come from parish registers.