Craig
I wouldn't base your assumption of all the exams on Air law - I've got 2 degrees, Bachelors in Engineering and a Masters in a Mathematical subject, and I also hated air law and found it difficult, so don't assume that 'acedemic' people have it any easier.
The other exams are very, very different. If you have a practical job as you do I would have thought that you will probably find the rest OK. Hell if you can cut the timbers for a hipped roof, then I would have thought the navigation vectors would be a piece of cake!
Try Airquiz.com for testing yourself and get the books. If you can't work something out then ask around the club, someone is bound to have a little trick way of remembering whatever it is. Above all, go flying! Navigation etc is a lot easier when you can relate it to what you are doing in the air.