Name of “Margaret Ball” from, Katia, wife of Tim Grant Oliver, in an email dated 29 August 2021, located a marriage record dated 3 February 1761 for a John Oliver and a Margaret Ball in Ashwater, Devon, England (login required):
https://www.familysearch.org/ark:/61903/1:1:NKYM-3LX
Name: John Oliver
Sex: Male
Spouse's Name: Margaret Ball
Spouse's Sex: Female
Marriage Date: 3 Feb 1761
Marriage Place: Ashwater, Devon, England, United Kingdom
Marriage Place (Original): Ashwater, Devon, England

(Tim Oliver is a x3 great grandson of James and Ruth Oliver, his grandfather being Ivor James Clark Oliver 1907-1989).

A burial document dated 3 June 1763 for Margaret with a husband of John Oliver was also found
https://www.familysearch.org/ark:/61903/3:1:S3HY-6...%2F1%3A1%3AQGNZ-74PX
Register of Ashwater for the Year 1763 Delivered into Court at his Lordship's Visitation held at Okehampton June 5th 1764.
"Margaret Wife of John Oliver was buried June 3rd"

Image from Katia in an email of 12 July 2022 for “The Year 1760, Banns of Marriage between John Oliver, Thatcher, and Margaret Ball, both of this Parish were publifhed on the three Sundays underwritten:
That is to fay,
On Sunday the 21st of December by me P. Sherwin
On Sunday the 28th of December by me P. Sherwin
On Sunday the 4th of January 1761 by me P. Sherwin”
[Spelling using an “f” for an “s” as was the practise in those times]

Confirmation of marriage date and of John’s occupation from another Image from Katia in same email of 12 July 2022 for “1761, John Oliver, Thatcher, of this Parish and Margaret Ball, spinster of this Parish were Married in this Church by Banns this third Day of February in the Year One Thoufand Seven Hundred and Sixty one by me P. Sherwin Rector. This Marriage was Folemnized between us: John Oliver, The mark of Margaret Ball In the Prefence of John Glanvill, Anthony Downe”.