I think it's probably a Dainty Soho Reflex, made by Kershaw and sold by Marion & Co later Soho Ltd. They were also re-badged as Ross and Beck reflex cameras. It's not the original 1908 model and is one of the later variations.
Ross list them as "The 3½ x 2½ New Focal Plane Reflex Camera" in 1910, Marion & Co as the Dainty Reflex, the early model has a different focus hood. By 1924 Ross are listing the standard Soho Reflex in their BJPA adverts.
At the time of introduction the cameras were used with 6.5x9 (2½x3½) Dark slides, Changing backs, and Film Packs the Rollex 6x9 backs were introduced sometime later.
Ian