I have loved this series. Love it's characters, stories, setting in both time and location.
That is why this last episode was so disappointing. In fairness, a finale to any series is tricky, especially a great series like this one was.
However, this episode strayed far afield from the rest of the series to the point it was unrecognizable.
Finally, if you watch entertainment in the UK long enough, you understand who it is that controls the narrative. This means you already know who will be portrayed as the villains in any movie, show, series, commercial, etc. It is sooo boringly threadbare, predictable, and over the top, it has become cringeworthy.
If you know what I am talking about, no explanation is necessary. If you don't know by now, no explanation is possible.
This unfortunate, clichéd storyline took away from the lifeblood of the series & seemed a hodgepodge of an ending to a truly great series.