Technically I think you're correct, but it's such a low level offence (even when carried out by a police officer), that it's probably not worth the effort/cost/court time/whatever. For me, disciplinary is the way to go. Then force feed the ******* jaffa cakes until the sight of them makes him mess his trousers.
Resources have already been wasted by investigating it in the first place. Not to mention the pointless BBC news piece. With that in mind, I say throw the book at him