Turning up smart and clean shaven gives a great first impression. I told you how all my aptitude test-mates looked! Like a sack of shit, most of them! One girl was so late she had to be rang- she was in bed- and no-one was interested at all. The girls were the worst, it has to be said. No effort whatsoever. And no common sense. And one wanted to be AET!
Don't keep getting yourself down over job history and exams- your chosen trade doesn't require GCSEs. Ok, you've got to do well on your test, but when they say they don't need GCSEs, they mean it! You're clever anyway, you always use good grammar. That counts for a great deal.