Start by placing the strawberries in a large pan with the sugar and cook for 2-3 minutes. Remove off the heat and allow to cool. Add in the defrosted blueberries, apple sauce, cold custard and zest 1 orange. Crumble half of the vanilla sponge, add to the filling and mix everything together. Roll out the pastry into a large rectangle and brush lightly with beaten egg. Slice the remaining sponge into 3 inch strips and place down the middle. Pile the filling on top carefully. Cut the extra pastry into strips, but still leaving attached into the center. Alternatively fold over the filling to create a lattice and trim off any ends. Place onto a baking sheet, glace with the remaining beaten egg and sprinkle over the extra sugar. Bake in the oven at 200°C for 35-40 minutes or until lightly golden brown. Serve either warm or cold with scoops of the strawberry ice-cream.