Scrub potatoes well and cut into inch & half cubes. Put into a large (2 quart)pot with a lid. Add enough stock to cover. Bring to a boil, reduce heat and allow to simmer while you perepare the rest of the soup. In a skillet, heat oil over medium low heat. Add cerely, leek and mushrooms. Cover and allow to cook on low heat until vegetables are partially tender, and juices are emerging into the pan. Stir occassionally. Sprinkle flour over the vegetable mixture, stirring constantly. Carefully pour 1 cup of stock into the mix, stirring constantly to prevent lumps from forming. Remove from heat and carefully stir this mixture into potatoes. Add remaining stock. Put soy milk into a bowl. Add a little of the hot mixture to the milk to warm it up before carefully adding it to the pot. Allow the whole works to simmer on low heat for 1/2 hour or more, stirring occassional to keep from sticking. Season with salt, pepper and curry as desired. Serve hot with garnish.