This seemed like just another YA problem novel when I started reading it, but I persevered because the author is Siobhan Dowd. Dowd only saw her first two novels - A Swift Pure Cry and The London Eye Mystery - published before she died of cancer in 2007, age 47. Since then, two other works completed before her death have been published: Bog Child and Solace of the Road. As far as I know, this is the last we will see. All of her books have been fabulous and have received many accolades. They are also quite different in style and tone from each other, but they all feature protagonists that feel very real. By the end of Solace of the Road, I cared deeply about a fictional young woman, Holly Hogan. Grade 7 and up.
For more about Dowd, see the Trust set up in her name.