Make up the bread mix to pack instructions, reserving a little of the flour for dusting, and leave to prove for 30 mins.
Line a baking tray with baking parchment. Tip the dough onto a floured surface and cut into quarters. Roll each ball of dough to a circle, roughly 20cm wide. Spread a little passata over each base, leaving a border of about 1cm around the edge. Season well.
Top with the peppers, sweetcorn, mozzarella, Parmesan, basil and blobs of pesto. Fold each base in half, to make a half-moon shape, then squeeze the edges together, rolling them a little to stick and create a seal. Cover the tray with cling film and leave for 10 mins. Heat oven to 220C/200C fan/gas 7.
Brush the calzones all over with beaten egg, then bake for 25-30 mins or until puffed and golden brown. Serve with dressed salad leaves.