Ways in which The Children's Book echoes Atonement

A little farther into A.S. Byatt's "The Children's Book" brings these thoughts: looks like a very good novel is unfolding, but I am totally daunted by the length of this book. I will read 600 pages of Moby-Dick, 1,000 of Ulysses, 1,200 of War and Peace - but for a contemporary novel, I'm not sure I want to devote that much time to one book. I know that's ridiculous in that I'm just as likely to read 3 mediocre 200-page contemporary novels so why not one good 600-pager. No reason. I'm reading on. I also continue to be struck by the resemblance or echo of Atonement: both historic fiction (Atonement about 20 years later than The Children's Book), but about eccentric and complex British families living on country-ish estates (Byatt's more eccentric and more political and artistic), both about class lines being crossed (a pernnial British theme - in Atonement it was more about upstairs/downstairs, in Byatt more about a true outsider, a Dickensian waif), both beginning with artistic performances at a family gathering (can anyone imagine this in an American novel? never), both about precocious children (another perennial British theme, are they all precocious), both seemingly to unfold over a long period of time. And you can't tell me Byatt is not aware of the echo, especially in that she pointedly uses the word "bryonny" (some kind of shrub? anyone who bothers to look up all her words will never finish the book), which is the name (differently spelled) of Macewan's protagonist. Britishh contemporary fiction is a small, crowded room with a lot of sharp elbows.