Mooney's first sentence is completely and utterly wrong.
I assume you are doing resits if you are only taking two, and as an instructor with BCFT I have taught many people from many different schools to pass the Gen Nav resit, including 8 who were on their last attempt before losing all their other passes (all of whom passed). One common factor in many of the failures is over concentration on feedback. Feedback might pass you on some subjects, but not Gen Nav and I suspect not Met.
Concentrate on understanding the basics, and actually what they mean. Do you know what the definition of convergence is? Conversion angle? Departure? Do you know why they are important? These are vital to recognising questions that require you to use them, and to using them correctly. Learn to use the CRP-5 quickly and accurately, and to distinguish questions asking for heading from those asking for track/course.
Once you know the basics, and feel you understand, then test your knowledge against the question banks, of which Alex's at Bristol Groundschool is an excellent example.
If you have any more specific questions then feel free to PM me. At the risk of advertising (but I don't think many offer it) I can offer private tuition on either subject, or directions to others who might offer the same including Met specialists.
Best of luck!