I second what Grandad Flyer says above. In some respects, particularly with the Alex Whittingham 2 day course, too much pre-study might be a disadvantage. He introduces you to a number of quicker and less complicated ways of tackling the problems thereby superseding methods you might already have self studied.
On my course there were a few of us who had done zero pre-study, but by the end of the course we were all able to pass the exam with very high marks.
My advice, if you are a quick learner, (no offence intended) is to get hold of a copy of the CAP "thingy" with all the graphs in it and only familiarise yourself with the way the graphs are read and the 1 or 2 chapters of text at the beginning ahead of the course, thereby leaving all your capacity for absorbing what Alex has to say.
This is all of course assuming it is Alex's course you're going on. I'm afraid I dont know about other courses so cant vouch for the above in their context.
Good luck.
------------------
"Airspeed is life.....Altitude is life insurance!"