If I may offer up an opinion?
As I see it there is a failure within the dealership network that leads right back to Mazda UK here.
Mazda UK seem to have at least some awareness of this issue hence the warranty work carried out on a number of cars. Some dealers seem to be aware of the issue whilst others deny all knowledge.
I would suggest that for the good of all ND owners, all those that have had this work carried out as a warranty issue, ultimately sanctioned by Mazda UK, contact Mazda UK and shall we say 'suggest' that they make their dealerships fully aware of the matter in hand via a service bulletin or recall, if they are reticent to do so I would suggest that you make Mazda UK fully aware that you are happy to contact trading standards and the relevant motoring authorities including VOSA of this potentially dangerous issue.
As I have said before, as far as we are aware this comes on gradually after a very low mileage, my concern for the bigger picture would be if one of the bushes/joints/links were to let go suddenly, this could result even at low speed loss of control of the car and running into another vehicle or worse pedestrian or children.
Mazda as an organisation are simply sh*t on customer aftercare and simply deny any issue or responsibility with any of their vehicles, many of which have had problems, I for one would not wish to see them in front of the wig for complete negligence perhaps causing a death i.e. corporate murder or manslaughter.
Just thinking out loud folks but it really is time Mazda took responsibility in whole for this known issue on the ND at low miles, fair wear and tear simply does not cut it.