Sounds very much like Maurice Bowra, a past warden of Wadham College, Oxford, England.

There was a male nudist area near the river called Parson’s Pleasure:

Parson’s Pleasure is now only a scene for tales from the folklore of the university. One anecdote has it that a number of dons were sunbathing naked at Parson’s Pleasure when a female student floated by in a punt. All but one of the startled dons covered their genitals—Maurice Bowra placed a flannel over his head instead. When asked why he had done so, he replied, “I don’t know about you, gentlemen, but in Oxford, I, at least, am known by my face.”

Classic Wiseposting