Place the flour, salt and half the cayenne pepper on a large plate and mix together. Cut the fish into pieces measuring approximately 3 x 2ins and place in the seasoned flour to lightly coat both sides.
Melt the butter in a large frying pan. Add the fish and cook gently for 3-4 minutes on each side or until light golden in colour. Carefully remove the fish fillets from the pan and keep warm.
Re-heat the butter in the frying pan. Reduce the heat. Combine the vinegar, cinnamon, mace, cloves and remaining cayenne pepper in a small bowl, and add to the frying pan. Reduce the heat.
Blend together the water and cornstarch. Stir in the tomato paste and add to the frying pan. Stir in the green pepper and bring the sauce to the boil.
Arrange the fish on a serving plate and pour the sauce over.