No not Mungo Jerry, the other one pretending to be the Prisoner?
It's not Patrick McGoohan's regular, long suffering stunt double Frank Maher. And besides which he's too short to play the Prisoner in close up, perhaps he was used in the long shots - in the distance like. I don't know who this chap is, and I don't know of any other fan of the Prisoner who knows who he is either. But whoever he is, he was also in the cavern back beneath the village!
Be seeing you