Debra Myhill supports teachers in learning the grammar knowledge they’re now expected to teach to rather young children. As you know, it’s a challenge if you haven’t been taught it yourself!
A Level language students should be ready to take this little grammar test for teachers. Try it out; it’s the first .doc on this page: https://socialsciences.exeter.ac.uk/education/research/centres/writing/grammar-teacher-resources/grammaraschoice/grammarsubjectknowledge/
There are some *really* great materials on that page to help you polish your understanding of grammar.
It’s also interesting to look over all the other materials suggested for teachers to use:
https://socialsciences.exeter.ac.uk/education/research/centres/writing/grammar-teacher-resources/grammaraschoice/