You can probably do this for a tiny fraction of the cost by buying a roll of a border or kiddy wallpaper, cutting out the characters and then sticking them onto a plain blue wall.

Worth a thought, you've a few months to get it done in!

Thank you for your ideas, i have thought of that, but i do really like the painted on effect. But if i cant find anyone to do it, i might look into it.
Thanks!