I've been a fan of this series since the beginning, even read several of the books, but I had only recently caught the final episode because shows like this tend to not have a satisfying ending. Oh glorious ignorance, how I wish I could still claim thee in this instance. While not a terrible episode, it definitely didn't live up to pretty much any others from the rest of the show.
After almost a decade, Gently is suddenly struck with grief over the loss of his wife. It's no surprise that he misses her, but it seemed completely out of character for him (or most adults for that matter) to become a blubbering mess about it after so long. Then there's the plot... and I use the term loosely. There are more Gently books by Alan Hunter than episodes made, and they went with a hackneyed government conspiracy story to end this series? Since they seemed forget he has MS, why not tailor a story where he relies on Bacchus and Coles to solve the case because he becomes symptomatic? That may be too difficult for these discount writers, but why wouldn't the 'antagonists' simply go after the MP who's causing them grief directly instead of using Gently to discredit him? Governments make deals with other governments all the time, so it's not something people need to get murdered over, making this story even more contrived so they could have their beloved dramatic... and unresolved, ending.
As I said earlier however, this isn't a terrible episode. The cinematography was excellent. I liked the score, even though it gave me a Tron: Legacy vibe. Bacchus and Coles were working well together finally, and there was a very touching scene with the three of them in the woods where Gently asks John about his 'going away do.' Overall though, I think Gently, and everyone else involved, deserved better. That's not to mean it should've been a happy ending mind you; there's nothing wrong with killing your title character off if done right (Morse fits that bill I think), this just wasn't it. With only two episodes this season/series, they may as well just not bothered and left us with 7 good years.