Preheat the oven to 180C/350F/Gas 4.
Heat the oil in a large saucepan and fry the bacon until crisp. Add the
onion and celery and stir until beginning to stick to the pan. Add the
garlic, cayenne pepper, herbs, tomatoes and seasoning and mix well. Stir
in the tomato sauce, rice and stock and bring to the boil. Gently stir
in the fish and transfer to an ovenproof dish. Cover tightly with foil
and bake for 20-30 minutes, until the rice is just tender. Stir in the
prawns and heat through. Serve sprinkled with the spring onions.