Start by placing the frozen berries in a pan with 1 tbsp water and sugar and cook down for 10 minutes to make a jam. Next, whip the double cream to soft peaks. Add in the cream cheese, lemon zest, icing sugar and vanilla and whisk together. To put together, break the sponge fingers into 3 pieces each. Dip into the soaking syrup and place 3 pieces into the base of each of 4 serving glasses. Spoon in a little of the jam, followed by the cream cheese filling. Repeat the process again with the sponge fingers, jam and cream.  Decorate the top with fresh berries and mint leaves and chill before serving.