Preheat the oven to 180˚C (160˚C for fan assisted ovens)/ Gas Mark 4.
Mix the eggs, oil, water and cake mix gently together and whisk (by hand or electric mixer) for 2-3 minutes until smooth and creamy.
Pour the cake mixture evenly into the two greased cake tins.
Bake in the centre of the oven for 22-25 minutes, or until a skewer inserted into the centre of the cake comes out clean. Leave the cakes in the tins for 10 minutes then remove and place on a cooling rack. Allow cake to cool completely.
Combine the coffee syrup ingredients together in a small bowl, then brush generously over the tops of the cakes. Refrigerate for 30 minutes in the tins.
Remove one cake from the tin and place on your serving plate ready to ice.
Fill the piping bag with the coffee icing, then pipe a spiral pattern from the centre of the cake until it is covered. Remove the remaining cake from the tin and place on top and repeat the spiral pattern.
Pipe vertical stripes around the sides of the cake. Using the palette knife, carefully smooth the lines, trying to avoid creating bare spots.
Sprinkle the grated chocolate over the top of the cake then carefully arrange the chocolate fingers along the side of the cake. Alternate the white and milk chocolate fingers until you have encased the cake.Cover and refrigerate