We've been going to Swanage 2 or 3 times a year. It is great in that it's just that little bit further to get to, so doesn't feel like London-on-Sea. Great campsites, especially Woodyhyde and Downshay. Woodyhyde has the steam train running along its edge, so is great for the kids, and Downshay you can walk to the steam train station and get in to Swanage or Corfe. Steam train runs late in to the evening, too, so you don't need the car! Stunning views of Corfe Castle from Downshay. Tom's Field is great, but not easy to get on as it's mentioned in Cool Camping. Loads to keep kids entertained and Studland beach offers shallow, safe water to swim. Fabulous walks all around the place. If you go early enough, recommend the chain ferry across from Sandbanks to Purbeck. Better than the drive around from Poole. Feel free to PM if you want any other recommendations. We know the area like the back of our hand!