Thanks for the update Andy
That is unbelievable, I cannot believe it is not a Safety Recall already, I would be more tempted to contact VOSA https://www.gov.uk/government/organisations/vehicle-and-operator-services-agency and report the information to them.
If they believe it is a serious concern then they can escalate it to BMW.
Huge error on BMWs part by using the wrong bolts that stretch and shear....probably overtorqued aswell