Put the sponge fingers in the bottom of 4 serving glasses. Drizzle over the Merry Berry and spoon over the jelly. In a bowl, whisk the cream with the icing sugar, lemon zest and most of the chopped mint leaves. Set aside.
Place a layer of sliced strawberries over the top of the jelly, then spoon over the custard. Finish with a spoonful of the flavoured cream, then decorate each with half an unhulled strawberry and the reserved mint leaves.