Possibly adding to the confusion, you mention the two baptisms at Benington of John (1774) and Joseph (1780), both sons of James & Sarah Warren. Searching for either a marriage or James' death, I found this:
11 Oct 1769, Marriage at Clothall - James Warren of Benington & Ann Cannon. Banns were also read at Benington & gave Ann’s parish as Risden.
The marriage is then followed by these baptisms at Willian:
15 Apr 1770 Anne d/o James & Ann Warren
23 Jun 1771 Thomas s/o James & Ann Warren
27 Feb 1773 Sarah d/o James & Ann Warren
23 Jul 1775 Elizabeth d/o James & Ann Warren
06 Sep 1778 James s/o James & Ann Warren
22 Sep 1780 Burial at Willian - James Warren, labourer
Just wondering if it's possible that James & Sarah weren't actually married but she was somehow able to assume his surname whilst he was living 10 miles away with Ann
