Did mine whilst still awaiting my FAC. I borrowed the course instructor's rifle.
What I would say is, if you have the opportunity to go with a friend and use their rifle, do it. Failing that, ask your fellow course members if you can try their rifle one evening before the shooting test, and use their rifle.
I only say this because, I did all my practice shooting with family & friends, without issue. I got behind the instructor's rifle and could not see the reticule at all. I said this, but was told I was not to adjust the scope as others were using it after me. I am a glasses wearer and this is unlikely to affect many people at all, but just something about that rifle scope and my eyes didn't work. Best to have that sorted before trying the test.