I was a fan of this series when most of the episodes were shown on PBS (here in America) around ten years ago. My wife and I loved the shows we saw then. I am sure I didn't see them all, so now that it is easily possible to do so with streaming services, my wife and I are starting at the beginning.
I am sure we did not see this one before. The plot is excellent, the acting excellent, the production values great. The basic idea of following the exploits of a police detective during war-time England is intriguing.
I must say, concerning this episode, that I'm a bit disappointed. I don't want to give any spoilers, but after about an hour, I was zeroing in on the main culprit, and I was right. But I envisioned a much more interesting scenario. I found the final resolution a bit too simple. Also, the side plot, introduced very early, about the music professor who was interred, had too pat a resolution.
Still, we are looking forward to seeing many more episodes in the months ahead.