4. At this point you are ready to add the dry ingredients.
NB While the recipe calls for self raising flour in our house we make our own by adding baking powder. The habit developed a long time ago after walking into unfamiliar commercial kitchens where I couldn't be sure just what was in the flour bins. People have a habit of mislabelling things and when you are using kilos of flour at a time the results can be interesting. About two teaspoons to 200 gm flour gives a reasonable result.
Sift the flour and salt together then add the choc bits and sultanas. Mix into butter with a spoon.Sorry, forgot a step...lick beaters
As you mix the ingredients be mindful of not crushing the mixture, you want to keep as much air in the mixture as possible. Towards the end as it amalgamates scrape the sides down. When there are no floury pockets present you're there.