KGVI 3d Pale Violet on 1942 Returned (unclaimed) Registered letter

1/3 letter rate with 3d registration opened by examiner.1942 London Foreign Section postmark. US applied markings. First and second notice handstamps dated September 8th and 15th. Undeliverable for reason stated- Return to Sender. British upon return. Red manuscript Saffron Walden location for Essex England return to sender. Tracing the Transit. 2nd Sept Registered at Paddington. 7th Sept Initial Receipt 8th Sept Attempted Delivery. 15th Sept Second Notice (on reply) 9th Oct Handstamp Unclaimed Manuscript Retour 3rd Nov Received back in London.