Further to last post, insurance company repaired the car after the f/o/s wheel sheered off completely, damaging the wing, door, bonnet edge, lower suspension arm etc.
They had the car for a month, but returned it with new wing, door and bonnet repaired. New f/o/s hub, lower suspension arm, new discs & pads, new wheel and tyre and wheel bolts.
All five wheel bolts sheared at 30mph.
The car has only been serviced by Mercedes or myself (trained mechanic/tyrefitter) and I tighten all wheel bolts tightened by hand, then torque wrench to 130Nm.
When the car has had tyres fitted, it has been by a high performance tyre specialist, who use a hand brace, then torque wrench. I stand and watch them as I'm OCD about this stuff.
YET....... the f/o/s wheel sheared all bolts at 30mph.... the detached wheel narrowly missing other traffic (luckily it 06:45am)