Thanks for the comments guys!
The way I did it was like this........
I printed the cartoon picture, cut it out into component parts like a jig saw, cut the shapes out in coloured icing and re-assembled them on the cake, painting the details on with colouring.
I'm quite happy to do weddings, birthdays, christenings etc...... as long as it's a cartoon themed event and I don't incur the wrath of any annoyed brides........