hi we had a similar problem,but found a lovely site by using the new search which gives you a 20 mile radius,the other way wehave got a site in the past [although its a risk] we have left it till good friday and ring round for a cancellation,its worked every time,happy camping.
Hi, Huntingdon Boathaven is in Cambridgeshire, between 2 villages called Huntingdon & Godmanchester. It has very good reviews on here (sorry don't know how to do a link). It's on the River Ouse, there is a boat marina, you can hire a boat or just crack open a bottle of wine, park yourself on one of the picnic benches on the riverbank and watch the world go by. We have a dog and there are lots of good walks, some to the villages & pubs. It sounds nice, we haven't been before but like you, I was beginning to think that we wouldn't get in anywhere for Easter.
Denise.
Don't forget to leave a review of the campsites you have visited this year or last!