This is the only recipe I make using cup measures rather than weights, which is why I have not provided weights in the recipe. I have used a 20ml Tablespoon.
I like to cut these into larger scones, because I never stop at one anyway. If you want to stretch the batch further, cut the dough into 12 smaller scones.
To make your own self raising flour, just add 2 teaspoons of baking powder to each cup of plain flour.