Here's my transcript of the will held at BLARS, extraneous bits excluded:
I, John Saby of Backnor House in the parish of Bolnhurst, farmer....
- to my son James £200 of goods and lawful money to be paid to him immediately after my decease and I appoint my friend Mr Edward Stockdale of Bedford, draper, guardian and trustee for my said son James (ie James was a minor)
- to my son in law Thomas Hartopp one guinea to be paid within six months of my decease
- to my four grandchildren, Thomas, Mary, John and James, issue of my daughter Sarah, wife of the said Thomas Hartopp, the sums of £25 apiece
- the residue to my son William Saby who I appoint sole executor
Dated 6 Dec 1777
Proved 9 Nov 1781
So his living children were
Sarah, wife of Thomas Hartop
James
William
Deceased child Elizabeth - "child of John Saby born Mar 6 1752, named Elizabeth, died in a few weeks"
Property would often/usually be disposed outside the will.
Also living in Bolnhurst was Joseph Sabey who had three wives all named Elizabeth, the first of whom was Elizabeth Hall. They baptised a son William on 26 Dec 1752 at Bolnhurst. I have him as marrying Sarah Throssell in 1785, but I could be wrong and it was William son of John who married Sarah. But there was a William, who I assume to have been the husband of Sarah Throssell, buried in Bolnhurst on 28 Feb 1827 aged 75. But the other William disappears after being named as executor of his father's will.