Preheat your oven to 200C (400 F) and line a large baking sheet with parchment paper (one without a lip is best).
In a large mixing bowl, add the all purpose flour, brown sugar, baking powder, baking soda and salt. Add the cold butter cubes into the bowl and use your finger tips or a pastry cutter to cut the butter into the dry ingredients. The mixture should resemble coarse bread crumbs. Now, add the pumpkin puree, vanilla extract and sourdough starter to the bowl and bring the mixture together into a sticky dough.
Now tip the dough out onto a lightly floured surface and push it out into a rectangle. You want it to be around 10 x 6 inches. You can make the dough into a round if you prefer.
Cut the scone dough into 8 equal sized pieces.
Transfer the scone dough onto the large baking sheet that you prepared earlier.
Brush the scones with milk using a pastry brush and place into the preheated oven.
Bake the scones for 20 to 25 minutes or until they are golden brown.
Once the scones are golden and baked through, remove them from the oven and place them onto a wire rack to cool.
While the sourdough pumpkin scones are cooling, prepare the two different types of glaze.To prepare the glazes, simply whisk together the ingredients for each glaze until the mixture is smooth and free from lumps. Once the scones are cool, pour over the white glaze and allow it to set. Then drizzle over the pumpkin spice glaze (you could also add this to a piping bag if you prefer).