I baked 4 8" x 8" square chocolate sponges and sandwiched them together with chocolate buttercream.
After leaving them to set for a little while I then began to carve the shape out, making a slight point to the front of the van and making the sides 'bulge' slightly. You will have quote a bit of wasted cake and the best way to use it up it to have a go at making cake-pops or a nice chocolate and cherry trifle!
Then I covered the whole cake in more chocolate buttercream in order to stick the fondant. My biggest tip would be to use white normal buttercream on the outside of the cake to stick the fondant to as it wipes off with only a little greasy mark. I had to cover this 3 times to get a clean finnish. No matter how many times you wipe down your table a little bit of chocolate buttercream always manages to find its way onto you cake once you have covered it!
After i had covered it with the main blue colour I used a round cookie cutter to make small wheel arches and then cut them away using a knife. To get a smarter finnish line the wheel arch with black fondant and make a raised arch on the outside to cover your joins.
I used a confectioners pen to write on the cake as my hand piping is not yet quite up to scratch.
Other than that I just tried to copy the cartoon picture, using my flower cutter as much as possible to make it easier. Then add a little silver lustre powder to finnish off the metal parts and job done.