Put the skimmed milk and bay leaf into a saucepan. Add the fish and poach for 10 minuted, turning once. Allow to cool slightly, then drain and chop the fish, reserving the milk.
Meanwhile, make the mint and yogurt sauce. Beat the spring onions, mint and lemon juice into the yogurt. Cover and chill in the refrigerator until ready to serve.
Melt the butter or margarine in a saucepan, add the onion and green pepper and cook over a moderate heat for 3 minutes, stirring once or twice. Stir in the chilli powder and cook for 1 minute. Stir in the flour. Pour on the reserved milk, stirring constantly until the sauce boils. Simmer for 3 minutes. Beat the sauce thoroughly Remove the pan from the heat, beat in the fish and season with salt. Beat in half of the egg. Leave the mixture to cool, then shape into eight flat cakes. Combine the breadcrumbs and chopped peanuts.
Beat the remaining egg with the tablespoon of milk, Dip the fish cakes into the egg mixture and then into the breadcrumbs and peanuts, to coat. Heat the oil in a non-stick frying pan and fry the fish cakes for 3-4 minutes on each side.
Spoon a little of the sauce on to each plate and serve the fish cakes on top. garnished with the spring onions. Serve the remaining sauce separately.