I took the dustjacket off the 1941 edition of Primrose Cumming's The Silver Eagle Riding School, so I could put it in a protective cover, which as you can see it was in dire need of, and lo!
this was on the other side.
I've never actually seen the dustjacket for Khyberie, so this was a double treat. What a shame it is to have to cover it up, but you can't have both sides of a bookjacket on display at once. This isn't the only double-sided dustjacket I've found, but it's the only one I've managed to photograph. I'm not sure whether this was strictly a wartime practice.