Make up the pizza dough according to packet instructions and turn out on to a lightly floured surface. Divide the dough into 8 pieces. Knead each lightly to produce smooth rounds, then roll into a 20 cm (8 inch) circle. Loosely cover with clingfilm.
Heat the oil in a large, nonstick frying pan and cook the peppers over a moderate heat for 5 minutes, stirring occasionally. Add the chorizo slices and cook for 2 minutes before adding the tomato. Cook for a further 3–4 minutes, stirring occasionally, until the tomato has softened. Remove from the heat and stir in the herbs and mozzarella.
Allow to cool slightly before dividing the filling between the 8 dough circles. Lightly brush the edges with a little water, then fold the circles in half to enclose the filling and press to seal. Place on a baking sheet and bake in a preheated oven, 220°C (425°F), Gas Mark 7, for 15–20 minutes. Serve warm.