[susan53]

The Orwell example is interesting - because it's not logical grammatically, and officially a "mistake". As you say, had been should be used. I think here there's the tension between the fact that he's writing about the past, but uses "at present" (meaning "at that time") to give the narrative a sense of dramatic immediacy. That leads to confusion between the adverbials and the verb forms.
But sorry, what your teacher said is definitely not possible.