Preheat oven to 200°C/400°F/Gas 6. Lightly dust flat baking tray with flour.
Sieve flour and bread soda into a mixing bowl. Add the bran and sugar and mix well.
Rub in the butter until mixture resembles breadcrumbs. Stir in the blueberries.
Put the yoghurt into a measuring jug and make up to 200ml with fresh milk. Combine.
Add to dry ingredients and mix to a soft dough. Turn onto a floured board and lightly knead. Put prepared tin into oven to heat.
Press dough out to about 2.5cms/1" in thickness. Cut into 7.5cms/3" round scones. Place on preheated tin and put back into oven for about 20 minutes until risen and golden brown.