threestable,
I remember those books, I had them too. Unfortunately my memory is also blank with regard to authors and titles. Agree with the descriptive points you've made and the kidnapping storyline. A couple of other things that are lodged in my head for some reason are that the aircraft was a twin piston engine type and the airfields at Lydd and/or Lympne (when it was still there) were mentioned regularly in the stories.