It misses out a study that is slightly bigger than all of the NICE ones added together namely the Norwegien HUNT 2 study that was carried out over a ten year period
That might be because the study has nothing to do with statins - a person with naturally low cholesterol is not the same as a person with naturally high cholesterol taking statins. It's interesting but really not relevant here.
NICE did not recommend statins because they think that high cholesterol is bad and statins lower cholesterol (both these things may well be true though): They recommend it because fewer of the people treated with statins died compared to those treated with a placebo. If your doctor recommends statins then that's probably because you are like the people in those studies, leading him to expect you to benefit from the drug.
We have a theory about how cholesterol affects mortality. Whether it's correct is an academic question; perhaps useful for developing new treatments but not relevant to the question at hand - should I take this drug? Maybe a lower dose would be even best but that still leaves a high dose better than nothing at all.