Hmmm .... do they at Osprey think, they've got the right cover art for that Spanish Republican Aces? What I see is a Rata of the VVS and a Bf 109 F or G with Eastern Front markings ....

A scene which might have happened in early 1942 over Russia. Though I think that Polikarpov fighters were already taken away from the front by then. A bit far away from Spain, don't you think so? Osprey should overhaul that cover again.
On the other hand, that Blenheim Aces is surely something for my father's son ....