Put the mince in a bowl and add the onion, garlic, red pepper, herbs, sweet chilli sauce and breadcrumbs. Add the egg and season with a little salt and pepper. Mix well. (This is best done with your hands.) Shape the mixture into 4 large burgers, and place on a baking sheet lined with nonstick baking paper. Cover loosely and chill for at least 30 minutes.
Brush each burger lightly with the oil and place on the upper rack of the halogen oven.
Set the temperature to 200°C (392°F) and grill for about 12 minutes, turning halfway through cooking, until cooked through. Serve in the burger buns with crisp lettuce leaves and tomato and onion slices, and accompany with mayonnaise and relish or pickle.