Hi
If you look on the IGI, you will find that John and Mary did indeed have a daughter Jane, but that she was indexed on the IGI under Tennett. She was born on 3rd February 1816.
John and Mary also had the following children (All baptised in Narborough):-
Ann Jennett 18/11/1802
William Mackqennet 30/6/1805
John Tennett 3/7/1808
Mary Jennett 1//7/1810
John Tennett 1/9/2/1813
Elizabeth Jannett 8/8/1820
James Hutchins Jannett 22/2/1823
Do not know where Mackqennet came from!!

If you look on the PRO's Site (Now the National Archives), you will find that William was in the Army. He served in the 13th Dragoons, and was discharged aged 34, in about 1839/40.
Rachel