I was a RS client and student. Not a member of staff. I went to a term or two of adult evening clases for the Stable Management Stage 1.
I did not take the exam. But I did then go on to help out at a RS yard for half a day a week for several years. So I was doing things with the horses and not forgetting what I had learned.
If you are taking Stage 1 with a view to doing Stage 2 and 3, i.e. while working at a yard, you are likely to find Stage 1 very easy. But with all tests the secret is to look closely at the syllabus. Know the exact answers required and put in lots of practice and self testing.
And as I say, one forgets skills one does not practise regularly. In theory I knew how to put on a bridle but the reality was that I did not unravel it in my mind nor do it well until I began to share a horse and had to tack her up twice a week.
But I had to rug my very first lesson horse after every lesson, so I can rug a horse with no bother at all.
For years I rode out escorted by girls taking the BHS exams. Stage 1 is very simple. Stage 2 is more like a GCSE, you need to learn things not usually known by the average amateur RS rider. And Stage 3 is more like A level. One may need extra practise and specialist tuition.