PaulJ,
I can certainly see why you're miffed and I also think the steering is probably verging on dangerous on my car as it is now for higher speeds, and it sounds as though yours is the same or worse. I can't remember when your car arrived but I think from reading other posts that you probably have the earlier steering, since it's only just coming through. Reports from my dealer BHM suggest the kickback is a good deal less violent on my car than on others they have driven. Would be interesting to hear what you think of the new steering and other mods.
I'll experiment and post updates and no doubt we'll hear other stories too. I agree that the factory needs to take a keen interest in resolving this, because it is only a matter of time before someone comes a cropper.
Looking forward to finding a nice wide smooth (private) road and taking it to 80 or 90 mph to see what happens. Hopefully this will not be my last post!!
Is your rear wheel mounted about an inch left of centre as you look from behind too?