A week somewhere near M1

[belly36]

...but not too near the M1!!!

We live in London and we're having one week in Durham in august. We'd like to stay somewhere for another week on the way home. Thinking Derbyshire, Nottinghamshire or Leicestershire. But I have no idea where or what there is to do for a four year old.

Other constraints - budget, looked at Centreparks but I think it is out of our price-range (over £1000 for a week). Would be probably looking at a cottage rental.

Any recommendations/ideas?

Thanks

Peak District ?ie Buxton/Bakewell

Have booked a cottage two miles from Matlock, thanks

Was just about to recommend that area - lots to do. Matlock itself has a lovely park with a splash area and boating lake. Gullivers is great too - quite hilly though. Heights of Abraham are okay as well - quite pricey and the little ones can get a bit bored when in the mines.