1. Preheat oven to 220ºC. Lightly dust a baking tray with flour.
2. Sift wholemeal flour, flour, soda and baking powder into a bowl. Return husks left in the sifter to the bowl. Cut or rub butter into flour mixture until it resembles breadcrumbs. Stir in sugar and yoghurt. Add sufficient milk to mix to a soft dough.
3. Press scone dough out on the tray to a 20cm round. Mark into eight wedges. Brush top with milk.