I am an international student so we don't have the grade system on instruments, however I think the requirement is to have passed the grade 8 on your instrument and then you should be fine. As far as I know, Sheffield doesn't require you to have done music as an A-level only the grade 8 if you're doing performanceit's great that you've already learned hangul, I'd also definitely recommend just practicing reading, learning some very basic grammar and vocabulary just so it won't be too overwhelming once uni starts.