Well let's face it at £824 it's hardly a bargain for one of the more cut-price Charter companies. It's worth checking if that includes everything (ie bags, food etc.).
I know it's all about supply and demand during the leak summer hol period but that's a flight that you can get for half that normally. Crazy crazy prices!
Edit-don't know how restricted you are n dates but I've just found Thomas Cook 23/8-6/9 Gatwick to Sandford for £623 pp flythomascook.com