I have achieved some relatively happy hunting today and have managed to dig-up the following. In the first picture I posted in reply No.6 you can see the rear of an aircraft with the serial number K.4299, this was the Armstrong Whitworth prototype to P.27/32 (won by the Fairey Battle), the AW.29. The aircraft sustained considerable damage when it was forced to land with one of the main undercarriage wheels retracted. However, AW got a contract (subcontracted to AS motors) to repair the aircraft and modify it to fly with a Deerhound II using the forward flow cooling configuration. However, it was then found that the forward flow cooling configuration was unsuitable (one assumes overheating) so work was suspended. In the meantime Whitley K.7243 flew with the reverse flow cooling configuration utilising the under cowling air intake as seen in the pictures, this was apparently successful and it was decided to transfer this cowling to the AW.29 so that Whitley K.7243 could be fitted with a new installation using wing duct cooling.
This of course never happened, in part because AW were so overloaded with other work that K.4299 ended up being stored outside. But also the scope of required changes to the airframe and its limitations as a test-bed, compounded by a lack of Deerhound IIs, made the exercise not worthwhile. Then Whitley K.7243 crashed on take-off (nothing to do with the Deerhound) on the 6th March 1940 so it never got its wing duct cooling.
Apparently work on the Deerhound II was stopped after the crash of K.7243 but was restarted after in 1940 which is when the Deerhound III emerged only for that to be abandoned after the bombing of the ASM facilities on the 8th April 1941.