How do you "search" the database? I have spoken with mates who would just click on the mock exam button and do the practice tests. Unfortunately this runs the risk that you will miss some of the questions as they are generated randomly.
It isn't made all that clear on the website but under the search function you have different ways of working your way through the database. The first is to just do all questions from start to finish as a mock exam (say 600 odd for POF, 900 in MET etc). The 2nd and a much better way if you don't want to be sat at the pc all day is to tell the programme to give you a batch of questions. For example you can tell it give you numbers 1 to 100 say and then on your next visit do 101-200 etc. My approach was to do it this way and type into a word document any questions that I struggled with along with the question ID number. Then after a few weeks I would go through all the problem childs as a final refresher by searching just on those particular questions with their associated ID number.