Hi John ...
Having checked the OFHS's Oxfordshire Marriage Index (1538-1837), I can confirm that there's no record of an Ann DEAN(E) or DEEN(E) marrying a George NICHOLS (or variants) in the county.
As Bodicote is not far from the county boundary with Northamptonshire, I also checked the MI for that county and found the following:
19 FEB 1816 - George NICHOLS (otp bach) to Ann DEAN (otp sp) at Aston-Le-Walls CofE
Aston-Le-Walls is approx. 12 miles north of Bodicote, so it would definitely be worth investigating this further.
Pennie