Preheat the oven to 220ºC, fan 200°C, gas mark 7. Put a baking tray in the oven to heat up.
Sift the flour and baking powder into a large bowl. Using your fingertips, rub in the butter until the mixture resembles fine breadcrumbs, then stir in the dried blueberries and 3 tablespoons of the sugar.
Make a well in the dry mixture, then pour in the milk and mix with a knife until you have a soft dough. Turn out onto a lightly-floured surface, knead lightly then pat into a round shape about 4cm thick.
Cut out scones using a 5cm fluted cutter. Re-knead the leftover dough and cut more scones until it is all used up.
Brush the scones with a little of the extra milk and bake on the preheated baking sheet for 10-12 minutes until risen and golden. Cool on a wire rack.
Meanwhile, put the fresh blueberries and raspberries in a pan with the remaining sugar and cook for 7 minutes until you have a syrupy consistency. Let cool.
Serve the scones cut in half and topped with the clotted cream and compote.