Mix the chicken, tomatoes, sweetcorn and chutney together, then stir in two-thirds of the cheese.
Roll out half the pastry on a lightly floured surface and trim to a 30 cm (12 inch) square. Brush with the egg, then spoon the filling over the pastry in 9 evenly spaced mounds.
Roll out the remaining pastry until a little larger than the first layer, then place it over the other pastry square. Gently press down around the filling, then cut into 9 squares with a knife or pastry wheel. Transfer to an oiled baking sheet.
Brush the tops with a little more beaten egg, sprinkle with the remaining cheese and bake in a preheated oven, 200°C (400°F), Gas Mark 6, for 20 minutes until well risen and golden. Serve warm or cold with salad.