Sorry for the copy/paste, but this explains just about everything about this car:
"According to Martin Bennett's book "Rolls-Royce & Bentley: The Crewe Years" (3rd edition, 2011), chassis 4AF6, a 2-door convertible, was returned to Rolls-Royce: The third PIV built, and the second delivered to a customer, was 4AF6 for the Shah of Iran. The coachwork was again by H.J. Mulliner, but the huge drophead coupe body, which was finished in a light metallic blue with white leather upholstery, was by no means characteristic of this coachbuilder. It was the only Phantom IV to have built-in Silver Dawn type headlamps. The car was returned to Rolls-Royce Ltd in 1959, it is believed because it had proved insufficiently stiff, flexing severely on Iranian roads. The outcome was that the company scrapped it, though the body survives on a Phantom III chassis, which perhaps suggests that the fault lay with the chassis. The car made its way to the United States in 1982, apparently from Switzerland,[10] still with its metallic blue paint. Recent photos of it (2000s)[11] exist online, but its current whereabouts are unknown."