DH and I are getting the in-laws to look after both kids a week Wed and Thurs nights. Have looked at lots of lovely hotels but a lot of them are near on £200 - £250 per night. We'd quite like one with a lovely spa area and pool so that we can just go and "loll" around all day. I do so much stuff with the kids that I really just want to do very little !!....For eg we have a Crowne Plaza near us which has just been done up to a really high contemporary standard with a lovely new pool and spa. I'm happy to do something like that so that we can enjoy and maybe find somewhere outside the hotel for dinner. I'd stay at that place save that it's a walk away from my house !!>.... Anywhere in Bucks, Berks, Dorset, Hampshire would do.
We just stayed in the one in Farnborough which was lovely (only opened in March). We paid £98 for two nights but I think your problem lies in that youre going midweek which is more expensive because they cater mainly for business guests.
Have a look at laterooms.com, if you can wait until a night before to book you will get it much cheaper.
I've booked the Macdonald in Bath - thanks Mufti....yep £270 for a classic room with breakfast. Rooms don't look too "frilly"(!) if you see what I mean. Also got dirt cheap fares on the train - only an hour from me and booked two singles each way as an advanced purchase and it was £34 in total. Probably the same as the petrol and at least we won't spend our time in the traffic or looking for a space (we drive everywhere but went to bath on my sisters hen weekend and loved the train journey).