Preheat the oven to 200 degrees C. Make egg wash by mixing egg, water and 1/4 teaspoon salt. Roll the sheets of pastry to half the original thickness. Remove a small strip from all edges. With assistance of a little flour, roll the sausage meat into 1 1/2cm rolls. Cut the sausage to the width of the pastry and lay 2cm from the bottom edge. Dampen the pastry on the other side with water.
Fold the pastry over the sausage and roll to cover. Cut nearly to the base making 5 incisions (to make 6 small sausage rolls).
Place long rolls on baking tray then brush with egg wash. Make two small slits in each roll. Bake in preheated oven until crisp and golden, about 15 minutes. Cut each roll into 6 small sausage rolls and serve with tomato sauce.
These can be frozen and then reheated in a hot oven.