Put the sultanas and rum or bourbon in a smallish saucepan and bring to the boil.
Remove from the heat, cover and leave for an hour if you can, or until the sultanas have absorbed most of the liquid, then drain.
Preheat the oven to 170ºC/150°C Fan/gas mark 3/325ºF and get started on the rest. Put the flour, baking powder, bicarb and salt in a large bowl and, using your hands or a wooden spoon, combine well.
Add the remaining ingredients to the dry bowl and gently fold in until mixed. Scrape into a loaf tin (23 x 13 x 7cm / 9 x 5 x 3 inches) and bake in the middle of the oven for 1-1¼ hours. When it's ready, an inserted toothpick or fine skewer should come out cleanish. Leave in the tin on a rack to cool, and eat thickly or thinly sliced, as you prefer.