Preheat oven to 220 C. Place lamb in a roasting dish and brush with a little oil. Roast for 20 mins to serve pink or 25 mins if you prefer a little more well done. Remove the racks from the roasting dish. Cover with foil to keep warm. Place the roasting dish onto a low heat element and add the flour to make a smooth paste. Stir in the red currant jelly, orange juice and stock. Bring to the boil, stirring. Simmer for 3-5 minutes until thickened and smooth then stir in the soy sauce and port. Cut each rack into cutlets and arrange three onto each plate. Serve with sauce and seasonal vegetables.