Note: I have not found any proof this book exists outside its mention at the back of the first two books.
"Kevin Sheldrake is no longer in the secret intelligence service but instead of being able to devote his life to his research, he finds himself drawn into a shadowy world of intrigues and violence when he agrees to help a fugitive from a little-heard-of country. He becomes embroiled in a deadly game between his erstwhile colleagues in the Service as well as international gangsters, the CIA, missionaries and NGO's. The most deadly web, however, is that spun by the fugitive he agrees to help."