Mix graham cracker and melted butter until well blended . Press mixture into a 9 inch pie plate. Cool in refrigerator. Melt the butter and sugar into a non-stick saucepan over a low heat, stirring all the time until the sugar has dissolved. Add the condensed milk and bring to a rapid boil for about a minute, stirring all the time for a thick golden . Spread the caramel over the base, cool and then chill for about 1-2 hours. Meanwhile whip the heavy cream with the vanilla extract and confectioners sugar, until soft peaks. Place sliced bananas over toffee. Topped with a whipped cream. Finish with the grated chocolate. Refrigerate before serving.