I got 4/5 of the way through this very lengthy book, enjoying the ride itself but not understanding what the heck it was about. Then I read the back cover blurb. Oh! It's about morality! Yes, it is, but the ride is so long and interesting in and of itself that this got diffused and diluted. So, now that I know what it's about, I like it even more. I would recommend keeping this blurb in mind as you read. I found the latter 1/5 even more enjoyable because I knew what Henshaw was getting at.
Try not to be put off by the length... As I said, it's a really nice ride. You stay with each family member (of 2 families) from youth to middle age and because of how long it is, you learn a great deal about how each character thinks and changes over time. If there's anything amiss, it's that aspects of people's character change often, without warning, and/or you don't learn about a basic fact of someone's character until very late in the book (take Francis, for instance). I would bet a million dollars that Henshaw did this precisely and on purpose, but it's sometimes off-putting. Keeps you thinking, of course.
There's also the British aspect of this that I always enjoy so much. Not just the fact that they say they're "off to hospital" and all that, but that life is the same and yet slightly twisted. I mean twisted because it feels as if everything (food, housing, jobs, traffic, etc. etc.) is about 15 degrees off from "normal." It's strange, in the nice sense of strange.