Preheat the oven to 200˚C fan / 220˚C / 392˚F convection / 428˚F.
Line a square 20cm x 20cm / 8" x 8" baking tin with baking paper.
In a large mixing bowl add the flour, baking powder, icing sugar / confectioners sugar and salt and stir to combine.
Add the cubes of butter and lightly rub the butter in to the flour with your finger tips, until the mixture resembles breadcrumbs. Stir in the lemon zest.
Pour in the milk, water and lemon juice and mix until just starting to come together.
Add the roughly chopped white chocolate and stir to combine, using your hands to bring it together.
Roll out the scone dough on a lightly floured wooden board using a lightly floured rolling pin, to a thickness of 3 cm / 1.2".
Using a 5 cm / 2" scone cutter or round cookie cutter, cut out circles and place on the lined baking tin.
Gather the scraps of scone dough, lightly bring them to gather and roll out, then repeat until all the dough is used up.
The scones should just about be touching in the tin – this helps them to rise.
Place in the preheated oven and cook for 13-15 minutes until lightly golden.
Cool on a wire rack.
The scones are best served on the day they are made, however store any leftover scones in a container for up to 2-3 days.