From the same seller as the GWR ARP badge from a few days ago is this fake GWR ARP armband on eBay. Claimed to be original but in reality a fantasy item.
Update: It would now appear that this armband and similar ones for Southern Railways (SR) and London North Eastern Railways (LNER) are being regularly sold on eBay by the same seller (with different accounts) with a rather dubious history in fake items. The originality and provenance of this armbands is now considered to be highly suspect. Given the lack of originals and little or no photographic evidence of armbands like this ever being worn, the old adage of 'buyer beware' comes to mind.
News about interesting insignia, ARP related info and period photos that turn up.