Next best is £12.93 (inc. delivery) at Amazon UK. I presume it is £7 instore.
Bickering brothers David (Andy Serkis - King Kong, LOTR) and Peter (Reece Shearsmith - League of Gentlemen) kidnap Tracey (Jennifer Ellison) in a desperate moneymaking scheme and hide out in a remote cottage from her ganglord father. However, feisty Tracey turns the tables on her bungling captors and escapes into the woods with peter as her hostage. Only this land belongs to a maniacal farmer and he doesn't like trespassers... Cue a grotesquely comic battle for survival- who will survive and what will be left of them?