Judge John Deed is (in my opinion) a great TV show. It takes a swipe at "the system" and "stuffy convention". I think it plays to the same sense of right and wrong that Inspector Frost did, in many ways. It's not meant to be "reality" but rather fiction based on reality.
The relationship between John Deed and Jo Mills gets played to death, and is very trying for the viewer to watch at times. The whole "will they or won't they?" thing is overdone. And how many times can a reasonably smart professional man make the same mistakes that jeopardise his career over and over? I guess maybe the hook for the viewer here is "how is he going to get his bacon out of the fire THIS time?"
It's still a great show, and Martin Shaw is great in the role. It's been said that he's not the best actor ever to be born in Britain, (The Professionals was a bit of a joke, sorry, and The Chief was a bit better) but he can play a lovable rogue, that's for sure. I think he plays the part of George Gently rather well, too, but that's another review.
Just let go and remember that it's not real, and it can be an enjoyable show.