Preheat oven to 220 degrees Celcius
In a large bowl combine the dry ingredients (whole grain flour, self-raising flour, sugar, salt, and baking powder)
Chop the butter into small chunks and rub together with the dry ingredients until like breadcrumbs
Combine the chocolate chips and raisins with the mixture then add the milk and water
Mix very gently with a metal spoon and stop as soon as the mixture is combined (over mixing will result in flat hard scones)
Gently press the mixture together and tip out onto a lightly floured surface (it should look like it could fall apart quite easily)
Shape into a large rectangle around an inch and a half thick (4cm approximately)
And cut into 12 rectangles.
Grease a large baking tray and transfer all of the scones onto it
Brush each scone with a generous topping of egg, then bake for 15 minutes, checking they are not burning on top
Remove from the oven when ready and cool for at least 10 minutes before enjoying with lashings of butter.