OK ..... the will of Thomas Sykes late of Stagsden but now of Bedford, Yeoman, signed & dated 18 June 1774, witnessed by John Martin Sykes & proved 19 May 1777 on the oath of executors & trustees Simon Trapp, lace dealer & Negus Easton, carpenter, both of Bedford.
.... to my dear wife Mary sum of £100 to be paid within 6 months of my decease and also all my household goods & furniture
.... to my youngest daughter Sarah Sykes the sum of £25 to be invested in securities to provide a legacy she can have when she reaches age 21
.... to my brother John Sykes such wearing apparel that executors think proper
.... all the rest & residue of my estate goes to my seven children, viz... John, Abraham, Isaac, Alice, Mary, Anna Maria & the said Sarah
So from birth/baptisms of children of Thomas & Mary Sykes of Biddenham
This is first wife Mary Negus of Oakley married at Ravensden on 29 Apr 1738
She's buried 23 Jun 1766 (Moravian) age 50
Wife Mary is Mary Gummer who Thomas married 3 Mar 1767 at St.Cuthberts
She died 6 Dec 1810 at Bedford (Moravian) aged 88
John baptised 23 Jul 1744 at Biddenham
Abraham born 17 Dec 1749, baptised 22 Dec 1749 (Moravian)
Isaac born 3 May 1756, baptised 3 May 1756 (Moravian)
Alice baptised 8 Apr 1739 at Ravensden
Mary born 16 Nov 1747, baptised 2 Dec 1747 (Moravian)
Anna Maria ? not seen her mentioned before
Sarah born 5 Oct 1762, baptised 13 Oct 1762 (Moravian)
? so where's Elizabeth baptised 23 July 1744 Biddenham
Conclusion .... John Sykes who married Fanny Fisher at Bromham is most likely son of Thomas & Mary Sykes, originally from Ravensden, then of Biddenham & then Stagsden.... but there's nothing that proves these are the couple baptising children at Higham Ferrers, but it is very likely.