The great Welsh poet Dylan Thomas showed up for the location shoot of the race car speed test on the beach at Pendine Sands, which was near his home in Wales. He can be spotted briefly at the start of the scene, at 1:11:03-04, as the hatless man in the brown jacket and beige trousers at the extreme left of the crowd in the background (ignoring the family of three on the left) about one-fourth of the picture's width from the left. This is the only known surviving motion picture footage of Thomas.
On the beach, around 0:05:40, Geoffrey says aloud to himself, "'The measure of love is what one is willing to give up for it.' Who said that?" Though the quotation comes up a couple of times more (Around 0:24:50, he answers, "Some Greek said it -- I can't remember who."), the question of who said it is never answered. The answer is, none other than Albert Lewin himself, the writer of the story and the screenplay and the director.