An example occurred last year in the United States. Their research undermined the preferred, idealised image of pre-conquest Native Americans, and provoked widespread disquiet. Some suggested their work should have been suppressed. British archaeology has its own explosive subjects. Celtic identity may be one.
Gender is certainly another.
Beyond PC I abhor this kind of virtual censorship not only because it impedes the progress of genuine research, but also because PC interpretations are themselves typically flawed by over-emphasis on certain aspects of the evidence, and they shift with the times. In time, these interpretations too will change. The business of the spirited historian or archaeologist is to question prevailing orthodoxies and find fresh ways of looking at the past. The pity of the Irving case was that he gave honest revisionism a bad name. Let us hope that publishers are not persuaded to avoid respectable, challenging thinkers in future as a result.