Can anyone identify this biplane?
Maybe it is one step before the Gladiator: The Gloster Gauntlet. Here the number of wing struts and the landing gear are a better match.



Gloster Gauntlet (picture source)

It must be noted that a lot of experimentation went on with those aircraft. The one in the picture above has guns added on both wings which made the aircraft too heavy and were removed later.

The type in your picture clearly has a different engine with a smaller and deeper NACA cowling - maybe it was used for testing the Bristol Mercury engine of the Gladiator.