Chocolate Ding Dong Cake

Name: Ding Dong Cake
Ingredients: 5 sheets gelatin, soaked in water for 5 minutes; 700ml double cream; 70g icing sugar; 1/2 tsp vanilla essence; 2 x boxed devil’s food cake mix, made as per the box ingredients; 200ml double cream; 200g dark chocolate, chopped; 200g caramel sauce