Paella in the oven

Name: Paella in the oven
Ingredients: 400g can chopped tomatoes; 600ml chicken stock; 1 tsp smoked paprika; good pinch of saffron; 1 onion, chopped; 1 garlic clove, crushed or finely chopped; 2 tbsp olive oil; 300g paella rice; 4 chicken thighs (skin on or boneless), cut in half; 200g chorizo, sliced; 150g raw king prawns, leave the shell on a few if you prefer; good handful of frozen peas; 1 lemon, quartered (optional)