This is yet again, another flawed system that the MOD have purchased. I have already seen how it can be passed by people who normally could not.
The idea, is you complete the laps in the quickest time possible, but your HR over the last 400 m has to be at a level, which tallies with the time you did it, and you age.
Now, I have seen a chap do it last week, who did as most will do, and do all the laps constant, and failed.
He then took some advice, tried it a week later and passed, and you can't tell me he got fitter in a week.
So what did he do, well, he simply went as fast as he could for the first 3/4 without running, to get the time down, then slowed it right down, so when you hit the 400 m point, your HR has come down, and you simply walk the last 400m casually. This, after to doing the maths, shaved over 2 mins of his previous time, and got his Hr down in the measuring period, and gave him a pass
Flawed? You bet.