General Navigation for me is a huge pain. On my second try now, first time around I failed by 2 points because I ran out of time with 10 questions unanswered for which I had to guess on. . . no luck.
Find out what question bank you are using. Bristol does not have the CQB15, while Aviation Exam claims to have it, and with what I am seeing and feedback from others who have taken the test, it seems they do have many of the questions that are popping up in the CQB15 exams. So if your country uses CQB15 for exams, I would recommend Aviation Exam over Bristol.. even maybe without it given the depth of information, and feedback given with Aviation Exam. Bristol is pretty bare-bone for the General Navigation exam. However for everything else it was fine.