Heat the oil in a frying pan and add the beef, a few pieces at a time, until it has all been added to the pan. Fry over a high heat, stirring until browned on all sides. Lift out of the pan and transfer to a casserole dish.
Fry the bacon and onion until golden, then add the wine, stock, tomato purée and mustard powder. Add 2 bay leaves and season generously with salt and pepper. Add the cornflour mix, bring to the boil, stirring until thickened, then pour over the beef.
Cover the casserole dish and bake in a preheated oven, 180°C (350°F), Gas Mark 4, for 2 hours until the beef is very tender. Heat the butter in a clean frying pan and fry the shallots until golden (about 5 minutes). Add to the beef casserole and leave to cool.
Divide the beef mixture between 4 × 300 ml (½ pint) individual ovenproof pie dishes. Cut the pastry into 4, roll one piece out between 2 sheets of clingfilm for a pie lid. Brush the rim of a dish with beaten egg, remove one sheet of clingfilm, lay the pastry over the dish, then remove the top sheet of clingfilm. Press the pastry on to the dish edge with fingers dusted with rice flour. Trim off the excess pastry and fork the edge. Repeat until 4 pies have been made. Brush with egg, add a bay leaf to each for decoration, then bake in a preheated oven, 190°C (375°F), Gas Mark 5, for 20–25 minutes until the pastry is golden and the filling piping hot.