My guess would be, that MG dealers are dealing with problem on a purely individual basis.
Investigate the customer complaint, then wait for MG themselves to provide the necessary permission for the dealer to order the parts.
Then after a long wait for the parts, install the replacement steering column ( that includes the troublesome UJ joint ) and ship the car out !.
MG themselves must be a acutely aware of just how many steering columns they are authorising to get replaced surely !.
I guess there will be a tipping point in the process, when somebody starts asking the question ??

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“Why are we replacing all of these steering columns prematurely on brand new cars ?”.
I have said this before, but I was a little surprised when problem was first identified on the Gen1 models, so early in the life of the car.
Also, even more surprised to find that the steering column assembly was a Bosch unit !.
But after saying that, the UJ joint section of the column is probably sub contracted out anyway.
Rarely does motor manufactures have a single point of supply of car parts.
Not wanting to have all of their eggs in one basket, so to speak.
Not every single car appears to be affected by this problem, so it is very likely that only one of the supplies are to blame here.
If so, it should be easy enough to identify which supplier is at fault.
Or is it just easier to switch out the faulty parts on the effected cars and move on !.
I would suspect that this is the mind set to be honest.
Problem here is of course, you could end up getting another defective component fitted onto your car !.
As we all know, the parts supply problem is extremely difficult right now, so shutting down one of your many suppliers, is very unlikely to happen in this current climate.
MG will be asking for reimbursement of these items from the supplier at fault and will happy to accept that.
Keeping the production lines going is more important to them, than replacing a few steering columns !.
The fact that these replacement steering columns are on long back order, goes some way to supports my theory.
Every steering column they take from baulk stock in China, to supply to U.K. dealers, could mean another new car can not be built.
We are about two years down the road since this problem was first identified on the Gen1 model and it is now transferred over into the Gen2 facelift.
If they intended to do anything to resolve this issue 100% then it would have been totally rectified by now.
Again, clearly they are only dealing with issue on a individual one by one warranty claim basis.
There is definitely either a design or more likely, an assembly issue with these UJ joints.
Lower steering column joints are rarely replaced in the life cycle of a car.
So, replacing them on a car that has only covered a very short mileage is NOT normal and identifies that there is a problem, with out any question in my mind.