1.Place tomato sauce, Worcestershire sauce, barbecue sauce, honey and mustard in a bowl and stir until well combined. Cut racks in half so there are 4 cutlets in each.
2.Place racks in a large dish. Pour tomato sauce mixture over racks, turning them to coat evenly in the mixture, then cover and refrigerate for several hours or overnight.
3.Remove racks from marinade, reserve marinade and transfer racks to a lightly greased baking dish. Bake in a 190°C (170°C fan forced) preheated oven for 30 minutes. Remove dish from oven, drain off any excess fat and brush racks with reserved marinade. Return racks to oven for a further 15 minutes or until lamb is cooked to your liking.