Very Chocolatey Celebration Cake

I originally got this recipe from the bbc good food website:  http://www.bbcgoodfood.com/recipes/1190635/bestever-chocolate-layer-cake.
Then:

1. When making the icing, use an extra 1/2 on top of that recipe.
2. After sandwiching the layers together, use a palette knife to neatly spread icing around the sides and on top of the cake. It doesn't matter if it is not perfect, the sides will be covered.
3. Use white chocolate buttons (inexpensive from most shops) to cover the sides of the cake. Make sure to do this neatly. Then, around the top of the cake, place an extra row of buttons just at the edge.
4. Finally, decorate the top of the cake with a message or any other decoration of your choice. I used white chocolate writing icing (you can get this from supermarkets) to say 'Happy Birthday Elizabeth xxx'.

It will go down a treat!