1. Preheat oven to 220°C/200°C fan/gas 7.
2. Toss the sliced pepper and onion with the oil and fennel seeds and roast for 15 minutes.
3. Prick the pizza base with a fork before topping.
4. Mix the barbecue sauce and tomato purée with 5 tbsp water and spread two thirds of it on the pizza base.
5. Add the remaining sauce to the chicken and toss well to coat it.
6. Take the roasted pepper mixture from the oven and spread on top of the pizza.
7. Scatter over the tomatoes then evenly spoon on the barbecue chicken.
8. Sprinkle with the cheese and bake for 15 minutes.
9. Serve with a green salad and coleslaw.