Looking for title of short story about time travel

"The Choice" by Wayland Hilton-Young, first published in Punch, March 19, 1952. The beginning:

Before Williams went into the future he bought a camera and a tape recording machine and learned shorthand. That night, when all was ready, we made coffee and put out brandy and glasses against his return.

The ending:

"I can remember only one thing."

"What was that?"

"I was shown everything, and I was given the choice whether I should remember it or not after I got back."

"And you chose not to? But what an extraordinary thing to—"

"Isn't it?" he said. "One can't help wondering why."

You can read the whole thing here or watch the film here.