I don't want to say whether you are or aren't being unreasonable as I don't think that's your issue here at all.
You need a list of things that are going on in your area.
Try the phonebook for soft play, pottery painting.
Are there any nice rivers, lidos, swimming pools that you could take her to.
What about a bit of shopping, or a day of pampering, you could both go to a beautician (i'm sure they won't make you pay more than a pund or two to whack a coat of nail polish on your daughters nails and you get a manicure into the deal, or do it yourself at home.
Do you have a link magazine or equivalent in your area? (List's things to do, events for pre schoolers).
What about fruit picking followed by a spot of pie/crumble making?
What are you local stately homes, tourist attractions like? Can you go for a nice walk somewhere?
Can you get anywhere on a train for a day out, the seaside, the countryside or a town depending on whichever one you don't live in?
Any free museums, butterfly houses, owl and otter sanctuaries, castles, caves or lord knows what near you?
Do you see what I mean, you're bored, unfortunately the job to thinking of something to do falls to you.Ring up your tourist information, do you have a childrens advisory service for your area (this kind of info is usually at the front of the phonebook) they'll point you in the right direction.
Don't wish away this time with your lovley daughter, once the education system begins, that's it, game over unless you're willing to pay horrific prices to take her away somewhere.
I'm sure there's some lovely stuff to do out there. Have fun!