It's easy for me to say don't worry but ........ don't worry. The guys down at Bristol really know there stuff and as long as you have put the work in beforehand they will teach you what you need to know to pass the exams. Try to complete the frames a week before you go to the brushup and use that week to revise the basics. I managed to pass all of mod 1 first time so they can't be that bad
Good luck