Those are available in a slim paperback, from Penguin.
It's entitled "The Character of Physical Law" and they are transcripts of his BBC radio lectures, with pencil sketch illustrations. I used to have a copy of it around somewhere.
NOT to be confused with "The Feynmann Lectures", a very classy, lavishly illustrated, three volume set available hardbound and in trade paperback, transcribed by his students from class notes.
Very "Philazawfigal". Damn, I miss him.