This two-book set features Shane Peacock's Last Message from Seven (the series) and Double You (The Seven Sequels). In Last Message, Adam finds out his grandfather's will requires him to go on a mission to France. When he gets there he has not one but three near-impossible tasks to fulfill. Life is no less complicated for Adam in Double You, which takes him (and a Walther PPK) to Bermuda, where he encounters danger, evidence of espionage and an unusual girl named Angel.
Check out Separated by Shane Peacock (The Seven Prequels) and all the other books in Seven (the series), The Seven Sequels and The Seven Prequels.
This edition is not currently available in bookstores. Check your local library or search for used copies at Abebooks.