1. Preheat the oven to 190C/375F/gas mark 5. Make the pastry by putting the flour, suet and salt in a large bowl, mixing thoroughly. Make a well in the centre, add the water, a few spoonfuls at a time, and mix with a large metal spoon. Keep adding the water until you have a firm, but not sticky dough.
2. Place the dough on a lightly floured surface and knead lightly until smooth. Roll out with a rolling pin to a rectangular shape 30.5 x 15cm/12 x 6in.
3. Skin the sausages by slicing through the skin and squeezing out the meat into a bowl. Mash all the meat together with a fork and then spread evenly on to the pastry, stopping 2.5cm/1in from the edge of the rectangle.
4. Moisten the bare pastry edges with water and roll up like a Swiss roll. Seal the edges and ends together and lay, seam side down, on a greased piece of foil.
5. Loosely wrap the foil around the roll, place on a baking sheet and cook in the centre of the oven for 20 minutes, then remove from oven and unwrap the foil, exposing the roll. Return to the oven and bake for a further 50 minutes. Serve immediately, cut into slices with mashed potato, steamed carrots and gravy.