OK. I found the part causing the problem. I must have missed it the first time I thought I'd suppressed all imported parts. Once I found and suppressed all imported parts the drawing views generated normally. I then re-introduced each imported part into the model. Of all the errors that I'd originally found when I ran Tools -> Check, this problem part only had one geometry error. It was a simple enough part that I created a new model to replace it and the problem is solved.