Preheat the oven to 220°C conventional / 200°C fan / Gas Mark 7. Line a baking tray with baking paper.
Place the gluten-free self-raising flour, baking powder, salt and optional garlic powder into a large mixing bowl. Stir until combined.
Add the cold dairy-free butter and rub it into the flour using your fingertips until the mixture resembles fine breadcrumbs.
Set aside approximately 25g of the grated dairy-free cheese for topping. Stir the remaining cheese into the flour mixture until evenly distributed.
Mix the dairy-free milk and lemon juice together in a jug.
Make a well in the centre of the dry ingredients and pour in most of the milk mixture.
Gently bring the ingredients together using a table knife or spatula. Add the remaining milk gradually until a soft, slightly sticky dough forms. You may not need every drop.
Lightly dust the work surface and your hands with gluten-free flour. Turn out the dough and gently bring it together. Avoid kneading it heavily.
Pat the dough into a round approximately 3cm thick.
Cut out the scones using a 6cm round cutter. Press the cutter straight down without twisting, as twisting can prevent the scones from rising evenly.
Place the scones on the prepared baking tray. Gently bring the remaining dough together and cut out more scones until all the dough has been used.
Brush the tops lightly with dairy-free milk and sprinkle over the reserved grated dairy-free cheese.
Bake for 15–18 minutes, until well risen and golden on top.
Transfer the scones to a wire rack and leave them to cool slightly before serving.