What aircraft is this?

[ATTACH=CONFIG]228075[/ATTACH]
It is part of a collection taken by one of Imperial Airways staff starting in the late 1920s. Unlike many of the others it has nothing written on the back. So all I think I know is that it was taken at Croydon sometime in the 1930s. I had several ideas for what it might be, but every time I compare it to photos of something similar I find differences that seem to rule it out. :apologetic:

Help please!