At least it seems like he can do good graffiti? Why not let him loose on buildings round London and say draw stuff with an Olympic theme, it would be a cheap way of getting London decked out into the spirit of things and if the murals are good leave them and they can improve the look of the area and serve as a lasting memento. Lets be honest the official Olympic graphics (that they've commissioned at high expense from professional companies) are crap.
Save the asbos and banning orders for scallies that want to write stuff like "MCFC champions 11/12" on walls.