Keep searching steph I'm sure something will turn up out of the hundreds of york hotels .Did you try the tourist board office also run a seach here .http://www.visityork.org/accommodation/hotel-bnbs/default.aspx

I came up with one that would take a booking for the night you need .Looks nice but it isnt cheap. http://www.judgeslodgings.com/accommodation.html

also the parsonage country house hotel had a room available with jacuzzi for one night but it's 5 miles outside of york.

I will not be defeated