Mr Dan Metcalf 
The Eagle of Rome A Lottie Lipton Adventure [PDF ebook] 

Welcome to the British Museum, home to Lottie Lipton: nine-year-old investigator extraordinaire!
When a collection of Roman treasures comes to the museum, Lottie, Uncle Bert and Reg discover the legendary code of the Ninth Legion”s Golden Eagle.
Can Lottie and her friends break the code and find the treasure before a ruthless treasure hunter gets his hands on it?
Perfect for developing and newly confident readers, Lottie Lipton Adventures are packed with action, adventure and puzzles for the reader to solve.