Thanks Bri. I also did some digging and found a Flight International Archive for the Dec 20 1921 issue it stated
For the power plant two 420 h.p. Liberty engines, driving four-bladed tractor screws, are mounted on the lower plane centre sections. Originally, two 210 h.p. Hall-Scott " L.6 " engines were fitted, driving pusher screws, but the former engines have been installed to ensure a larger reserve of power —especially when flying on one engine—and a higher speed.
Quite a change in engine power.
Regarding the challenge aircraft, I agree the vertical fin/rudder profile is reminiscent of DH but I am unaware of any connection.
Mel