May I ask a question? Let's suppose I go to London, I phone the Daily Star, they interview me and I say: "I am an expert in finding buried bodies and for the last five years I investigated the case of Xxxx, a British child that vanished in 2007. I found that she was killed and her body is buried in the garden of the private residence of Mr. John Doe. Just dig it, and you will find the body".
A murder is a crime and police (either Scotland Yard or PJ) has legal powers and a duty to act whenever they heard, read or find any new piece of evidence about a crime that has been committed years ago. What is expected that Scotland Yard will do, after they read the news about my "discovery"in the Daily Star?