Use a rolling pin to roll the dough to a rectangle approximately 40 x 20cm(151/2x8in). Spread the melted butter over the entire surface, then sprinkle over the sugar, cinnamon and chopped apples. Roll from the long edge, making sure you get it as tight as possible, then cut into 12 pieces using a sharp knife. Place on the lined baking tray, cover with oiled clingfilm and leave in a warm place until doubled in size and the buns are all touching each other. Preheat the oven to 180C/Gas Mark 6.