Melt the chocolate, butter and Agave syrup together in a heavy bottomed saucepan then set aside for about 5-10 minutes until cooled but still runny.
Line a loaf tin with a sheet of baking parchment or loaf tin liner
Place the marshmallows, biscuits, popcorn, apricots, hazelnuts and cranberries in a large bowl, pour in the cooled chocolate mixture and stir until everything is well combined and coated in chocolate.
Tip into the prepared tin and flatten as best you can with a spatula, refrigerate for at least 3 hours, preferably overnight, until set then lift the slab out of the tin and cut into slices. Keep refrigerated.