Mix together orange and lemon zest and juice with garlic, ginger, mint, seasoning and yogurt in an ovenproof dish. Make a number of cuts in the chicken flesh. Place in the marinade and cover. Chill overnight. Bake at 190 C / 375 F / Gas 5 for 50 minutes, until cooked. Pour cooking liquid into a blender and process until smooth. Serve with chicken on a bed of rice garnished with lemon and orange zest.