I would be inclined to ask MBUK as they are known, why their wheel bearings, hubs, and sensors only last 26000 miles.

Put this in your letter/email:-

I can assume one of two scenarios:-

1 That MB tested the subject components, found that they were sub-standard but fitted them to production vehicles regardless of the consequences.

or

2 That MB did not test the subject components at all, and fitted them to production vehicles regardless of the consequences.

Could you please advise me of which scenario applies to the parts in question?

That should get them walking on their hind legs.

There is a possibility that the car has suffered some abuse prior to you buying it. maybe it has been driven through standing water etc.

I had similar thoughts, wondered if it might have been standing in a part of a compound that flooded regularly, have you had a good look underneath to if rust is evident in the lower suspension parts....have you subjected the car to deep water or severe dust roads regularly?

Assuming you haven't caused this i sincerely hope MB fixed this under warranty or goodwill, they've been making cars 4x4's and serious commercial vehicles long enough to know not to make bearings out of cheese.