One of my primary school teachers (p3, perhaps?) read us a story book, 'The Grammatical Kittens' which painlessly introduced us to grammatical terms such as nouns, verbs, adjectives etc. If we could absorb those terms, presumably the Y6 children of today know how to use terms such as determiners. As GS and GD both achieved Level 5, I have to assume that they had learnt all about modern grammatical terminology and were able to apply it. Unsurprisingly, I am told by one who knows these stats, that far fewer children reach level 6 in English than reach it in Maths.
One of the more peculiar questions in my Higher English paper (almost 60 years ago) was: "Write sentences using 'round' as five different parts of speech".