I prefer British films to US films generally,
Salmon Fishing is a definitely not the type of film Americans make. No ridiculous emphasis on families with fathers acting as the all-knowing fount of wisdom. No stupid singing. No nudity. No tongue gymnastics. No sanctimonious and fatuous smiles. No canned laughter. No abuse of people from a different culture.
This is a film about people and progress. Different types of people walking side by side yet with different goals. Different versions of progress.
I liked the realistic, but not common, nature of the story.
I thought that parts of the ending were a little too neat, but other parts were very thought provoking and delightful. Certainly the filming itself is beautiful. Sets are wonderful. Dialogue is fine.
This is a film for adults and not little children, not because of sexual innuendo and language, but because of the geographical, political, and social concepts explored.
If you get an opportunity then watch Salmon Fishing in the Yemen. Here is a trailer