It’s a 9 Sqn aeroplane which carried the names of ancient Kings and Queens of Wessex. Two others were Caedwalla of Wessex and Caldwalla of Wessex when the Sqn was part of the Wessex Bombing Area circa 1928.
The photo is 90 deg out and that’s not a hedge, but the edge, of a piece of tape on the neg or the edge of a part frame (last)if the strip has reached it’s end or indeed the corner of a building.
In my view it’s a normal pic of an HP.42 sedately flying along and “snapped” too late.