I'm a yank. I learned of DI Frost a few years ago. I bought my first collection of Frost dvds in region 1 USA but this last in region 2 which I can play on my all region player. I couldn't wait for this last one to come out in region 1.
The first of the Frost series was so good I bought all the rest of them. The themes and personal parts of the plots were always interesting. The series is worthy of re-watching and I do that from time to time. Always depth in plots although some are more to my interest but none are uninteresting. Unexpected parts in the plot, ponderable personal events. Always well done from cinematography, music, plots, acting, directing and editing. There has always been more to Frost storys than entertainment in the mystery genre.
The 3rd ending is in the tradition of British mystery novels and tv series in my opinion but all 3 endings are worthy.