Firstly heat the oven to 220C/425F/Gas 7. Next mix together the salt, flour and butter. Stir in the cheese and then the milk until you get soft dough. Turn the dough onto a floured work area and knead lightly. Pat out to a round 2cm/¾ inch thick. Using a 5cm/2in cutter, stamp out the rounds and place them on a lightly greased baking sheet. Knead together the rest of the dough and stamp out more scones to use up all of the mix. Brush the tops of the scones with a little milk. Bake for 12-15 minutes until well risen and golden. Cool on a wire rack and serve.