Well Ultrafine films are sold by
Ultrafine Online who are listed in the Biz Directory here as Photo Warehouse.
There's nothing on their site to indicate who makes the Ultrafine films, but perhaps a small clue is their 125 ISO B&W film, maybe this is Ilford material from before their shake up, only Ilford make a 125 ISO emulsion. But a quick check on Wisner's site indicates the film is "Made in England" so it is Ilford
So maybe the 400 ISO film is Ilford HP5, that would make sense. The LF sizes are no longer available on the Ultrafin site.
Ian