Pre-War Test Pilot for De-Havilland?

Perhaps this is one for Bruce?

I am researching the background of Flying Officer Peter Frederick Cazenove who served pre-war with 615 Squadron and during early 1940 was with 92 Squadron. He was shot down over Calais in May 1940 (in Spitfire P9374) whilst serving with 92 Squadron.

On reviewing my notes made about thirty years ago when I interviewed his widow I see that he was “…a pre war test pilot with De Havilland’s”.

Can anyone verify this, or add any detail – or steer me in the right direction?