Hi Jean,
Checked OFHS Wantage PRs and there is no marriage for John in Wantage.
Have found this though.

Baptism
7 Sep 1792 John Doe son of Robert and Elizabeth
And i looked up the marriage of his parents for you incase you dont have it.
8 Mar 1791 Robert Doe, bach, otp, (X)
Elizabeth Puzey, sp, otp, (X) by banns
Wits John Smith, John Huccup
John Huccup seems to be named in a lot of the marriages so is probably the minister.
Could find no burials for Robert or Elizabeth in Wantage but saying that i have not searched
nearby villages.
Hope this may help

Sue
