Spray a large frying pan with low-calorie spray and place over a medium heat. Add the onion, red and green peppers and celery. Cook for 5 minutes until softening.
Add the garlic, paprika, thyme, oregano and cayenne pepper. Stir and cook for 1 minute.
Add the chicken and seal on all sides for 4-5 minutes. Add the chicken stock, bay leaves, chopped tomatoes, tomato puree and Worcestershire sauce or Henderson's Relish. Stir and then simmer, uncovered, for 20 minutes until the chicken is cooked through and shows no sign of pinkness.
Add the prawns, spring onions and lemon juice, and simmer, uncovered, for about 4-5 minutes until the prawns have turned pink and are cooked through. Take care not to overcook the prawns.
Taste and add the sweetener or sugar if needed (optional). Season to taste with salt and black pepper. Remove the bay leaves.
Sprinkle with chopped flat leaf parsley and serve with Basmati rice and any accompaniments of your choice.