We've recently been to Kneps farm, Thornton Cleavleyshttp://
www.knepsfarm.co.uk/. Its about a 15-20 min drive into Blackpool, and is on the edge of a country park. They have serviced pitches and normal ones, and a good amenity building with 10 individual bathrooms with bath, shower, toilet and sink in. Admittedly its not overly cheap, but a good site. It caters for all ages, but is also a quiet place. The also have a barrier system thats operated by ANPR.
As for Blackpool, the proms finished, but there's major work on the Tower and Winter Gardens. We went in the Tower, but only Jungle Jims, the Ballroom and the Circus were open and they still charged the same price as when it was all open.