Absolutely - keep plugging - it all starts to make sense in the brush up course.
When I went to do my ATPLs one instructor had a mantra that the brush-up was basically worth 15%. So, if you get more than 60% now in your practice test, you're doing about right.
Significantly less and you need to step up the work rate, and make use of all things that available to you - call the instructors, buy the published textbooks and read them thoroughly rather than just relying on the school's notes etc. etc.
Remember that a textbook costs ~£20, but a resit costs more than that, not including the lost time. They're a sound investment as they often give you a different angle on a subject.
cheers!
foggy (14 first time passes
).