ATIS31,
It's probably not THAT important and I'm sure it wont prevent you getting a job completely.
However!
Your CV is in a pile of thousands at the start, the last thing you need is anything jumping out at a prospective employer to give them an excuse to bin your paper and move on to the guy next to you, who hammered the question bank and can demonstrate a 90% + average with first time passes.
The good news is that, it's totally normal to feel that way during the distance study part, the 2 week brush-up course will get you fit for the exam and hammering the database, in spite of the rightness/wrongness of it all, is essential and will get you the results you need.
It is daunting, I was in a very similar situation to you. Like they say at the start of the brush-up. If you put in the work, you will succeed. Slog it out, you'll be fine.