Roll the pastry out thinly into a rectangle, then cut it lengthwise into 2 strips.
Divide the sausage meat into 2 pieces, dust with flour and form into 2 rolls the length of the pastry.
Lay a roll of sausage meat down the centre of each strip, brush down the edges of the pastry with a little milk, fold one side of the pastry over the sausage meat and press the two edges firmly together. Seal the long edges together by flaking.
Brush the length of the two rolls with milk, then cut each into slices 4 cm (1 inch) to 5 cm (2 inches) long.
Place on a baking sheet and bake in a moderately hot oven (200°C / 400°F / Gas 6) for 15 minutes; to cook the meat thoroughly, reduce the temperature to moderate (180°C / 350°F / Gas 4) and cook for a further 15 minutes.
Cover and brown the top of the dish under a hot grill.