Splendid spike, Spike!
Returning for a moment to the helmet in the photograph, you made a keen observation regarding its crushed top. As collectors, we tend to regard such damage as the consequence of years of neglect and indifferent storage.
Based on the Leutnant's wristwatch, spot and key studio lighting, and use of panchromatic film stock, I believe the photograph was taken in the mid to late 1920s.
Chas.