The wrong girl / Laura Wilson.

CRIME & MYSTERY. In 2006, three-year-old Phoebe Piper went missing on a family holiday. Despite massive publicity and a long investigation, no trace of her was ever found. Seven years later, Molly Jackson, aged ten and recently uprooted to a Norfolk village, finds her great uncle Dan dead in his bed. Molly remembers nothing of her early years, but she's been sure for ages that she is Phoebe. Everything in her life points to it and now, finally, she has proof. Dan's death brings his hippie sister Janice back to Norfolk where she's re-united with Molly's mother Suze, the daughter she gave up for adoption decades earlier. Janice discovers that a former lover, Joe Vincent, lives nearby. Joe was a rock star who, at the height of his fame, turned his back on public life. As she is drawn back into the past, Janice begins to wonder if Dan's death and Joe's reputation as a reclusive acid casualty are quite what they appear...And then Molly disappears.