Maybe not British, but it is very much a Japanese tendecy, ime. If I see a good anime/comic, I try to appreciate what I saw and expect no resolution. I'm curious how often they even have resolution in the outline.
A key thing with manga is that many series originally run in serial format in magazines that will drop the series and the author like a hot potato if popularity with readers wavers, so (a) it's impossible for the authors to actually plan for an ending and (b) authors are incentivized to insert whatever it takes to keep readers coming back based on this specific week in the real world instead of having a plot outline.
Every year has a slew of animes which wrap up in 13 or 26 episodes. A sparse few go to 52. An even sparser few fit the mold you describe, but even many of those end eventually with a planned conclusion (Bleach and Dragon Ball <Suffix>).
Sorry, I wasn't speaking in absolutes. I'm not a pollster or statistician, so I was relaying my anecdote. I think your comment's sibling, and one of mine, elucidate why I have that anecdote.
I just can't do that. I typically only watch anime that has ended so I know that there will be resolution. I really appreciate well thought out series.
In short, I appreciate the story far more than the story telling. The longer the story is, the bigger the payoff needs to be.
Perhaps that's the difference between British and Japanese audiences?