Put the biscuits into a large sandwich bag and crush into crumbs using a rolling pin.
Place the crumbs into a bowl and mix in the melted butter until thoroughly combined.
Spoon into a 20cm x 20cm loose-bottomed baking tin that has been lined with parchment paper and use the back of a spoon to pack it down tightly. Place in the fridge whilst you start on the next layer.
Add the cream to a large bowl and whisk to until the cream holds it’s shape. Add the cream cheese, vanilla extract, confectioners’ sugar then whisk again until combined.
A little at a time, fold in half of the salted caramel sauce. You want to make sure the cheesecake mixture remains thick and spreadable (so it can hold it's shape), so you may want to add in less caramel sauce if it looks like it's going to thin out the cheesecake mixture too much.
Take the biscuit base out of the refrigerator and spread this layer on top. Put back in the fridge for an hour. This will help it to firm up a little bit more.
Take out of the refrigerator and lift out the cheesecake using the parchment paper as a handle and place on a chopping board. Carefully slice into 36 pieces (6x6 squares). The cheesecake mixture will be delicate, so cut carefully.
Spoon the salted caramel into a piping bag or plastic sandwich bag. Spoon the melted chocolate into another bag. Cut the tips off and drizzle each cheesecake square first with salted caramel and then with melted chocolate. Place a tiny pinch of coarse rock salt on each square, then serve.