If you go onto "how to get the most out of ATPL online" on the website home page and follow the links to the learning objectives, below is a direct link. At the bottom of the links page is post and pre NPA. These links take you to the JAA learning objectives lists and explaines the topics within each subject relating to a specific learning objective. You are interested in the middle 2 sets of numbers which you input into the learning objective boxes when searching for questions on the database. This then brings up all the questions linked to that learning objective.
https://atplonline.co.uk/help/links.aspx
Hope this helps and is what you were after, I think AGK systems is under LO 021.