Preheat oven to 400 degrees
Place flour, baking soda, baking powder, salt and butter in a food processor and pulse until it resembles course crumbs. Alternatively, you can cut the butter into the dry ingredients with a pastry blender. Dump the mixture into a large bowl.
Mix the milk and 2 tbsp lemon juice together in a small bowl or measuring cup and let stand 5 minutes.
Meanwhile, add the sugar to the dry ingredients, then stir in the lemon zest.
Make a well in the center of the dry ingredients and add the milk, stir just until combined, then fold in the cranberries.
Turn the dough out onto a floured surface or large sheet of parchment paper.Gently press the dough into a 9 inch circle, then cut into 8 wedges with a sharp knife or pizza cutter. It is important not to handle the dough more than necessary or it will become tough. Place the wedges on a parchment lined baking sheet with 1 inch room between them.
Mix egg and 2 tsp of milk together and brush over scones.
Place in the oven and bake 20 minutes or until golden brown.
Remove scones from the oven to a cooling rack.
Allow to cool about 10 minutes. Then mix the powdered sugar and 2 tbsp lemon juice. Drizzle over the scones and serve.