This is definitely one of those "what the hell!?" books and I think I would hate it if it wasn't so perfectly British in how it tells the story of quiet tragedy and people just being people at one another. As a critic, I appreciate how deftly Allan handles the narrative and how every critique I have--such as finding certain bits in the middle unrealistic--is not so much a critique as an argument for reading the book a certain way. I'm annoyed because I want to read the book in the opposite direction, but squaring the circle either way is impossible and that's what makes it so brilliant. As a reader...I'm still a bit of a sucker for a neat bow and an authorial bow. The fact that I wanted one doesn't take away from the fact that Allan's book, from the beginning, lets you know it's not going to do that. But the ending is well-handled nevertheless.
Is quiet British tragedy a genre? I mean, it's the genre Kate Atkinson writes crossed with mystery and the genre McEwan writes crossed with whatever the heck interests him this week. It's intriguing to see it in SF.