If two share a basic room with food court food eating option for three nights and towels, sheets and cleaning included it only costs £286.80 between you (entertainment included in that as well). I think that's a bit of a bargain!
What else would anyone want to do in the depths of winter?
There isn't a day ticket option and my feeling is Steve would be on late on the Saturday night so no hope of leaving the party early.
Go on. Book a weekend away. You might even like it!