In a large skillet, heat the oil to a medium temperature. Add the drumsticks and cook, turning often, for about 10 minutes, or until browned on all sides. Add the tomatoes, chilies, brown sugar, and allspice. Bring to a boil, cover, reduce the heat to low, and cook for 20 minutes. Add the chutney, lemon juice, and raisins. Cover and cook on low for about 15 minutes more, or until a fork can be inserted into the chicken with ease. Remove the chicken to a serving platter.
Skim the fat off the sauce. Add the banana and heat thoroughly. Spoon the fruit and a little sauce over the chicken. Garnish with mango slices. Place the remaining sauce in a separate dish and serve warm with the chicken.