I did mine about 6 years ago now, still have yet to actually do a race
The flag test is utterly f*cking terrifying. It doesn't matter if you've been watching racing for years, and know exactly what each of them means, it's still sh*t scary knowing if you get one single one wrong that you fail everything.
I did mine with a bunch of others at Bedford, as part of a group thing organised by Patrick Mortell of Rogue fame. Really good laugh, the morning was spent out on track as an open pit lane day, and then the test at lunch with the practical in the afternoon. We had these utter sheds of VX220s to drive, gearbox was like stirring a bucket of bricks and I missed the gear on more than one occasion. Examiner was okay about it though, we were laughing and joking about how crap they were! Luckily for me this was after I'd owned the VXR so I knew how to handle the car, but some of the people there had never driven MR cars before: I suspect that was proper scary for them.