Weirdly, I actually read Fly By Night a long time ago for work (I was a newspaper book reviewer for about ten years, during the time that Fly By Night was published) and I don't think it left much of an impression, because it didn't make me want to rush out and read more of Hardinge's books. However, so many of my friends, particularly people whose reading tastes tend to align with mine, raved about her that I finally decided to give more of her books a try. I, like you, absolutely adored Cuckoo Song. My absolute favourite so far is probably A Skinful of Shadows.