Alan was my CAT IV teacher, and he was able to pass on in a very limited amount of time some substantial and complex concept to which I had not previously been exposed.
He has a very strong background and takes pride on following up on all questions raised during the class, irrespective of whether he can answer on the spot or if he needs to stay up the whole night to get an answer.
It was a real pleasure being his student and I recommend his courses to anyone who is involved in condition monitoring.