Visiting Oxford from Brackley I have found the following do reasonable priced meals.
Browns in the Covered market
University Club just down from Kings Arms in Holywell st, then left.
Wok and Roll , Woodstock Rd reasonable priced chinese and the chinese eat there as well.
By the castle there is a eat as much as you want just of the Wetherspoons Swan and Castle.
Far from the Madding Crowd friars entry between Gloucester Green and magdelan street prices £7- 9 .
To think that London, or anywhere else for that matter, does not belong to any one demographic