There is a possibility that the importer puts another better set of tyres/wheels on the car to pass the NCT then puts the illegal ones on again to get it sold.They're probably making only €1500 on each import so €400 for tyres might be hard for them to absorb on every car.
You're probably right.
Still, I got a whole year out of them and two winter spares should the weather change.
Had a retired NCT guy in the Car last night.
He reckoned that human error was responsible for allowing the winter tyres through.
As you say, it was common practice for fleet owners with the same model cabs to chop and change to get a heap through the NCT.
Then return the defective parts to the vehicle once it passed.