You can make this bread with as many raisins as you like. If you want to eat it plain with butter or clotted cream, it's best with lots of raisins. When eating it with marmalade or jam, add a smaller amount.
Add butter and milk to a small saucepan and heat till the butter is melted. Set to one side.
Mix all dry ingredients except the raisins in a large bowl. Separate egg and add white and half of the egg yolk to the flour. Set the rest of the egg yolk to one side.
Add milk mixture to flour mixture and knead with an electric mixer till smooth and elastic, about 2 minutes. Add the raisins and knead some more till they are evenly incorporated.
Preheat your oven to 100 C / Gas 1/4. If your lowest oven temperature is higher, preheat oven and turn it off once it has reached the temperature.
Tip the dough into a loaf pan. Using your wet hand, even out the dough so it fills the tin.
In a small bowl beat the remaining egg yolk with 1 teaspoon milk and brush the top with it.
Let the bread rise in the preheated oven for 30 minutes. Increase oven temperature to 200 C / Gas 6. Once it has reached the temperature, bake for 45 minutes. Turn off the oven and leave the bread in the oven for a further 10 minutes.
Remove loaf tin from the oven and let cool slightly, then turn out onto a wire rack and cool completely before cutting.