Preheat the oven to 180C/350F/Gas Mark 3 and lightly grease a baking sheet.
Sieve the plain flour and baking powder into a large mixing bowl.
Rub in the butter or margarine, using your finger tips to resemble fine breadcrumbs.
Mix in the wholemeal flour, caster sugar and salt.
In a separate jug, beat the eggs and mix in the milk.
Pour into the dry ingredients and mix until combined - it will be a soft dough.
Turn out onto a floured board and bring together. Try to avoid touching the dough too much as it will make the final scone tough in texture.
Roll out to approx 1 inch or 3cm thick.
Using a cookie cutter, cut the scones out and place on the prepared baking sheet.
Brush the top with a little beaten egg yolk if desired and sprinkle with seeds if using.
Bake for 15 minutes until the top is golden brown.
Remove from the oven and allow to cool for a few minutes before transferring to a wire tray to cool fully.