I use a food processor (Thermomix) to chop the nuts and chocolate, and to cut the butter into the flour. This is the method I have given below, but these steps can easily be done by hand if you prefer.
There is no added sugar in the scone mixture. If you like things a little sweeter, either use milk chocolate or add a couple of tablespoons of unrefined sugar to the flour before adding the butter.
These scones freeze really well. I reheat them by quickly zapping them in the microwave, but I have also wrapped them in foil and reheated them in the oven for dessert if the oven has already been on.