does UCAS automatically reject you if you miss a grade?Watch
Its up to the individual Universities to decide what they accept/reject on Results Day.
Many may still accept some applicants who are a 'near miss' if they have places on the course, so its worth aiming high just in case, and you'll have your Insurance if your Firm does say no.
How to Choose Firm and Insurance - https://www.thestudentroom.co.uk/a-level/
What happens on Results Day - https://www.thestudentroom.co.uk/res...el-results-day