place a layer of cookies into a lage trifle bowl of about 30cm in diameter and soak in a cap of port.
melt the chocolate in a bowl over hot water. when fully melted mix into half of the custard. layer the mix over the cookies just to cover
make a second layer of cookies on top of the chocolate custard mix and cover with the chocolate custard mix. repeat this step until the chocolate mix has gone.
whisk the cream and remaining custard till thick and peaking then spread onto the top layer of chocolate custard. crush two biscuits and sprinkle onto the cream mix. leave in the fridge till ready to serve.