Thanks, Gilly. Do you know if the faulty seat frame (track assemblies) were:
1) worn out,
3) incorrectly installed, or
4) incorrectly manufactured?
I presume the last two would have generated the MB bulletins you refer to.
I'm a bit concerned that seat parts could break or wear out in only 29,500 miles! If they did then it's a QA problem and a "moral warranty" claim - however many years the seat "waited in the garage" not being adjusted, and not even being sat on...