Hi Paul.
Well done on getting some flying in. Its been about 7 weeks for me....
Congrats on the Met as well. To be honest the Nav is far easier once you have done one or two lessons on it. That said, my school 'recommended' you do the exam before starting the practical.
My advice would be to study the whole syllabus before you start the flying, but leave the exam until later.
Back to the met I had a marginal question as well. It wasn't about ocluded fronts was it?