The Man at Six
[...] An Alfred Hitchcock super-special of which the title will be announced later [and] another Alfred Hitchcock production, "The Man at Six," the Queen's Theatre success [...]
It's possible that the "super-special" might be Rich and Strange, as that was the next film Hitchcock made for BIP.
The Man at Six ended up being given to director Harry Hughes and was released in 1931. The film starred Anne Grey, Lester Matthews, Gerald Rawlinson, John Turnbull, Kenneth Kove and Charles Farrell, and was retitled The Gables Mystery for the US release.