Preheat a fan oven to 190 C Gas 7 and line a large baking sheet with baking parchment.
Mix together the flour, mustard powder, baking powder, thyme and salt until well combined. Add the butter and rub the mixture together with your fingertips until evenly combined. Stir in the cheese and apples.
Mix together the beaten eggs and milk and gradually work into the flour mixture until you have a firm but moist dough,
Roll out the dough on a lightly floured surface until it is about 2.5 cm thick all over. Cut out the dough using a 3 inch cutter- you should get at least 8 scones and perhaps one or two more. Brush the scones with milk.
Put onto the prepared baking sheet and bake in the oven for 15-20 minutes keeping a close eye to ensure they don’t overcook. Serve immediately.