No, mixes are cake flour with the sugar and baking soda and everything except the egg and oil and water already in the package. This is how Americans cook. We cannot be bothered sifting flour and adding other dry ingredients. We buy it in a mix and then add the wet ingredients and whatever we want. They don't sell cake mixes in England? That seems so 19th century. The baking aisle at the grocery has all the mixes plus the basic flour and sugar type ingredients, plus the chocolates, in all their forms, butterscotch chips, mint chocolate chips, coconut, nuts, pie fillings, etc. all in one place.
The one thing we can't get here is something my daughter fell in love with in Holland --- Hagel Fagel. It's shaved chocolate in a box and you sprinkle it on pancakes and ice cream. I've looked everywhere.