I saw Tony Manvell who owns Wiltshire Rod and Gun in Swindon shooting Winchester shells at Southdown, wether they were trap 100s I have no clue. He had Winchester plastered all over his jacket and was shooting a Winnie auto so I assume he may well have a sponsor deal.
Could give him a bell and see if he is bringing them in for the shop. http://www.wiltsrodguns.com/