I think the one revealing stat NOT MENTIONED would be an AGE PROFILE of the 750,000 cars that failed
In saying that my own car is an 08 MX5 roadster ( 16 years this year ) and has passed with flying colours so far. Not gloating, its that kind of car that, in the main, one looks after well if you have one. I am trying to keep it on the road beyond it being a classic. Shes an Irish car and was lucky to get it hardly used in 2014.
I have an aquantance with a 92 Starlet, same thing, flys through the NCT annually. I suppose not much can go wrong with it, very simple and mainly old style mechanical w/o much electronic stuff :D
Any way - still, it would be informative to see an age profile of the cars that fail. Is it mainly those over a certain age OR is it a mixture of newer / older?
Of course as article implies, it could be the NCT really pushing the boundaries of its terms of ref with regards to what it checks or not