Proves what? Your post makes no sense Colin.
How about you stop skirting/ deflecting/ swerving and let us all know with a yes or a no whether you agree that manufacturers and sellers have more than safety on their agenda when they 'recommend' fitting all season tyres all round and not just on one axle?
It makes perfect sense if you take your blinkers off.
If you read the cut and paste in post 51 you will see the Conti have no problem with advising that fitting of only two tyres due to budget constraints or lack of availability is acceptable, and here's Michelins advice on fitting different tyres to front and rear.
Can there be different levels of wear on front and rear tyres?
The tyres on a car wear differently at the front and rear. When you buy a new car or change all four tyres at once, the tyres of a front-wheel drive car tend to wear out faster than the rear tyres. It is therefore normal to have differences in tread depth between the front and rear tyres. The law does not prohibit this as long as the wear indicators are not reached.
Replacing two new tyres: should you put them on the front or the rear?
Deeper tread tyres on the rear axle provide better handling, wet grip, and evacuate water, thereby helping to avoid oversteer and loss of vehicle stability on wet surfaces.
Deeper tread tyres on the front axle can improve wet straight line braking and stopping distance.
If only two tyres are being replaced, MICHELIN generally recommends they be installed on the rear axle in the absence of a tyre service professional's recommendation or consumer's preference to the contrary.
Can you put different brand tyres on the front and rear?
There is no law against it. For example, you can fit MICHELIN tyres at the front and another brand at the rear.
Can there be different treads on the front and rear tyres?
We have seen that it is possible to fit tyres of different brands at the front and rear. It is also possible to fit tyres of the same brand with different tread patterns at the front and rear
Can you mix winter and summer tyres on the front and rear?
Legally, this is not forbidden, but it is not what the Michelin experts recommend. Why not? Because road and weather conditions can cause tyres to behave differently.
For example, if you put summer tyres on the front and winter tyres on the rear: in winter, your rear tyres will grip well and you will not risk a spin.
On the other hand, in summer it will be the other way round: the summer tyre will grip better on dry roads and there will be a risk of "oversteering" with winter tyres on the rear. Oversteer is when the car turns more than it is told to do with the steering wheel: it is the beginning of a spin.
It is therefore not recommended to fit different season tyres at the front and rear, but if this is the case, it is preferable to fit summer tyres at the front and 4-season or winter tyres at the rear.