You can stay a Sunday night at the Malmaison in Oxford, which is pretty much in the centre of the town and used to be the Victorian prison! Has a lot of the original features!
Basically, if you book a room and have dinner in the Brasserie and spend £75 on the meal, they will only charge you a quid for the room! What's more, you get free porridge the next morning, lol! The menu looks nice and between 2 with wine should be at least 75 quid so I reckon it is a bargain and have booked up already for one of the May Sundays pre bank holiday.
Obviously if you spend more on the meal you have to factor that in, but the minimum they state is 75 smackers. See what you think.