Just to throw in my little bit; I think it is outrageous that you have been charged by the factory to put this right and even more so since you are a long term customer.
Think about this. If you had had a serious crash you would have been held responsible but most likely nobody would have ever thought that the cause was detached steering rack, and damage to the car might have precluded an investigation.
At the very least I think a letter to the CEO is in order but I think I would be getting legal advice. This is dangerous enough that there should be a re-call on all the cars fitted with this steering rack for a control and rectification.
Strangely enough I had a similar experience years ago with a Vauxhall Velox that belonged to my mother. The bolts holding the steering box in place came loose and fell out. Fortunately when it came completely adrift I was probably only doing 10 miles an hour having travelled only about 50 yards before the first left turn. It went off the road and I was just able to stop before going into a ditch. It was certainly a weird feeling not being able to steer the car. My mother was always somehow conviced it was my fault

Five minutes later and I would have been on the open road at at least 50 mph so I guess I was lucky. I was able to tighten up the one remaing bolt and drive it cautiously the 10 miles to get it home.