Spy Dog Unleashed by Andrew Copenhagen - old paperback

Age :7-11

Lara, or GM451 as she is known by the government, is a highly trained special agent, bred by the British Secret Service for use on dangerous missions around the world. But her last mission went wrong and now she is being hunted down by an evil drug baron, Mr. Big. Lara must go undercover as a normal dog, "choose" a family to look after her and await her retrieval by the Secret Service. But can she keep her true identity a secret?