Grease and baseline a 20.5cm/8in round tin with a depth of 4cm/1 ½ in.
Put the raisins, dates and brandy in a bowl and leave to soak for 30 mins.
Melt the chocolate, 125g/4½oz butter and syrup in a pan over a gently heat.
Add the biscuits, orange rind, raisins, dates and any remaining brandy. Mix well, pour into tin, cool and chill for 1 hr.
Melt the chocolate for the topping in a pan with the remaining butter. Pour over the biscuit layer. Chill overnight. Cut into wedges and pack into boxes.