I would think that cake flour is *self raising* flour.....
Cream of tartar is an easily purchased ingredient in the UK - usually added to scones and other non yeasted foodstuffs. I use cream of tartar and bicarbonate of soda to make scones rise up (a teaspoon of each for each 8 oz of flour).
Cake flour is a flour with less gluten made especially for cakes, it is milled from soft wheat. It produces a more tender cake with a finer texture than AP flour. If you can't find it, you can substitute 1 cup minus 2 tablespoons AP flour. Cake flour is not self rising unless is says on the box.