Preheat oven to 220c/430f.
Add plain SR flour (225g) and wholemeal SR flour (225g) to a large bowl and mix lightly to combine.
Add cubed butter (100g) to flour and using your fingertips rub the butter into the flour (or use a pastry cutter as pictured above) until the mixture resembles breadcrumbs.
Mix in finely grated parmesan (2 tbsp) and fine salt (½ tsp).
Add buttermilk (270ml/1 cup + 1 tbsp) to flour mixture and mix with a flat bladed knife. For the final few strokes bring the mixture together with your hands. Do not over-knead.
Turn the dough out onto a well-floured bench/board and knead the dough very lightly (only a few turns) until just smooth, then pat the dough out into an even piece approximately 2½ cm/1" thick.
Dip a round 6cm/2½″ scone cutter into some extra flour and cut out scones, being careful not to twist the cutter or touch the edges of the scones (see my notes). Lightly push together any remaining dough scraps and repeat.
Place scones onto a baking tray and bake for 12 - 15 minutes.