Heat oil in a 2 litre oven proof casserole dish, add onions and garlic and cook over low heat for 4 to 5 minutes. Stir in the broccoli and peppers; stir cook over moderate heat for 1 minute. Stir in the celery; stir cook for 1 minute. Stir in the tomato paste (already combined with the thyme), plum tomatoes and kidney beans. Stir in the rice. Pour in the stock and tomato juice. Add the bay leaf and bring mixture to a low boil. Cover tightly and place in a 350 degree oven for about 40 minutes until liquid is absorbed and rice is tender. Remove the bay leaf before serving. Serve sprinkled with grated cheddar cheese if desired.