The Jonathan Hare Series consists of Passe Partout - published by Libros Libertadin Canada

stairs In London, Jonathan gets the wrong side of a criminal gang. Then his special skills are spotted by an agency for the Establishment and he is sent to open a safe containing the liquid assets of a once wealthy aristocratic family. He opens the safe at their home, Mountbeck. He also helps to break up the gang and this brings him to the attention of senior government officials.  welbeck
Welbeck Abbey, the model for Mountbeck

Ignorant Armies - published by Melrose Books in the UK

ia Jonathan wins a scholarship to Oxford University. He is dogged by the enemies he made in Passe Partout and to escape their attacks has to employ more of his special skills. In the process he meets an important aristocrat who befriends him and who will have a major impact on his future career.  And the Intelligence Service decides to groom him for service as an agent. Oxford
City of Dreaming Spires

The story continues with books in progress -

The third novel is called Special Services in which Jonathan discovers new applications for his skills and expands the range of his clandestine contacts. This novel is now complete in first draft and is in local readership. The fourth novel is provisionally called The Hilary Term in which Jonathan is taken in hand by an Intelligence agent to widen his skill base.