Sift the oatmeal and flour with the salt into a warm basin. Cream the yeast and sugar and gradually work in the warm water. Stir the yeast liquid into the flour mixture to form a thin batter, adding a little more warm water if necessary. Leave to stand in a warm place for thirty minutes until well risen. Heat a griddle, hotplate or heavy frying pan and grease it lightly. Pour a small cupful of batter on to the griddle and cook for two minutes. Turn and bake the other side. Eat hot. These oatcakes can later be fried with bacon, or toasted and served with butter or dripping.