This is another of the dishes I've been brought up on. A warming, comforting dish, very nutritious and, without the dumplings, low in fat. The vegetables can be substituted, there are no hard and fast laws, after all, my nana makes it with whatever she has in the house! Feel free to experiment with combinations of vegetables. The only must is that the herbs are fished out before serving and that you serve with crusty buttered bread! I also like to liquidise some or all of the broth to give a thicker texture, though it then becomes vegetable soup. You may find you need more or less liquid--again, experiment.