I am a little disconcerted that Wenger didn't request a personal hearing so he could give his side of the story, as he actually had an extremely valid defence that Dean made it look like he had a vendetta against the Arsenal boss. (justarsenal.com)
The court also noted that protections of freedom of expression and freedom of the press could provide valid defences where communication of facts are in the public interest. (slaw.ca)
It may be interesting to know whether it would be a legally valid defence if true; after all, people have managed to fool juries (and judges) with lies before, and maybe the expert witness won't be believed. (law.stackexchange.com)