Ahhh..
Roy had been plagued by teenage thugs - Gary, still a bad-lad extraordinare at this point, breaks into the Cafe to rob it, Roy thinks its the thugs and wallops Gary with the bat.
Gary had thought Roy wasn't home, and comes to his defence later on, playing down the incident to the police, and Roy later offers him a job in the Cafe.
It does seem odd that CPS would go so hard, when its pretty easy to prove the back-story for these previous offences, ie, that Roy was defending himself from what he thought were vicious thugs (and to be fair, Gary was one at the time). Particularly when they still have no evidence that Lauren is even dead, let alone that Roy killed her!