Essentially, I was gripped by this and thought it was a well put together whodunnit/mystery with some excellent twists and turns. 
 However, and this may seem rather irrational, the title annoys me! Yes, the book was about "a woman" and she may, or may not have been, in "Cabin 10". Throughout the book, though, the narrator refers more often than not to said female as "the girl". 
 So, I think the author in her efforts to avoid being tarred with the "Girl..... in the Title" syndrome, went with "Woman". She then muddled a bit with both Girl and Woman in telling the story. 
 This doesn't detract from the overall story though, brilliantly narrated with intrigue and much suspense by Imogen Church, who I am quite a fan of now as a narrator.