1) Melt the 2 chocolates in a heatproof bowl set over a pan of simmering water.
2) Meanwhile, line a baking sheet with parchment paper. Using a ruler and a pencil, draw a 23 by 25cm rectangle on the paper. Turn the paper facedown on the baking sheet.
3) Pour the melted chocolate over the paper and spread to form a rectangle, using the outline. Sprinkle the cashews, apricots and cranberries over the chocolate. Set aside for 2 hours until firm. Cut the bark in 2.5 by 8cm pieces and serve at room temperature.