Done the course prep at Warsash a while back now though.
The best advice I can give is invest in a Mcneils seamanship examiner book, for mates/Masters.
If you know the answeres in the book (most of them!) you will pass.
When I did my Masters Orals, there was a group of 6 or 7 of us who would spend 1/2 the day just going through the book, plus the bouyage cards, and light cards etc etc. We were all well prepared and most of us passed.
Good luck where/when ever you do orals is also helpfull!