Via: Martin Poole
Grease and line a 20cm square tin with baking paper. Break up the spiced orange, dark and milk chocolates into small pieces and place in a heatproof bowl with the butter and syrup. Sit the bowl over a pan of barely simmering water and heat gently until melted. Remove from the heat and stir to combine.
Put the biscuits into a food bag, seal, and break into pieces with a rolling pin. Roughly chop the pistachios. Add three quarters of the crushed biscuits, pistachios, cherries and marshmallows and all the ginger to the chocolate and mix well to coat.
Spoon into the prepared tin. Scatter over the remaining biscuits, pistachios, cherries and marshmallows and press down. Chill for 1-2 hours until firm. Lift out of the tin and cut into squares.