Mix the flour, sugar, baking powder and salt in a bowl. Add the butter and rub together using your hands to form an even, crumbly mixture. Add the diced peach. Pour in the yoghurt and lemon juice, then mix quickly into a soft dough – do not knead. Cover and chill for approx. 30 mins.
On a lightly floured surface, roll out the dough to approx. 2 cm thick (approx. 20 cm in diameter), cut into 8 pieces, place the scones on a baking tray lined with baking paper, brush with milk, arrange the peach slices on top, sprinkle with sugar.
Approx. 25 mins. in the lower half of an oven preheated to 200°C. Remove from the oven and allow to cool slightly on a rack. Mix the icing sugar and lemon juice to create a thick glaze, drizzle over the scones.