The one issue I had was finding white vinegar, I'd gone to Sainsburys (local grocery store) to find it and they only seemed to have balsamic which is great but not in a cake! I ended up buying something called White Condiment and crossed my fingers that it was what I wanted (it was, nothing else on the planet smells like vinegar!).
Red Velvet Cup Cakes

2½ cups plain flour
2 tablespoons cocoa powder
1 cup buttermilk (substitute 1 cup of milk mixed with 1tsp lemon juice, let stand for 10 minutes or until curdled)
1 teaspoon pure vanilla extract
2 tablespoons red food coloring
1 cup butter
2 cups sugar
2 large eggs
1½ teaspoons baking soda
1 tablespoon white vinegar
Preheat oven to 350/180
Mix butter & sugar, add in eggs, vanilla and food coloring. Mix in coca powder, baking soda and vinegar. Alternately mix in flour and butter milk.
Pour into bun cases and bake for 15-20 minutes.
Cream Cheese Frosting:
8 ounces cream cheese (this should be one standard container of cream cheese, be careful otherwise you'll have too much - as I did)
6 tablespoons unsalted butter
1 teaspoon pure vanilla extract
2 cups confectioners’ (powdered) sugar
Mix all ingredients together in a high sided bowl, spread onto cooled cupcakes.