Alan...Bowler hat??? Nah...any proper Brit would want a hard hat shaped like the army pith helmets as seen in "Zulu!"
The French had a pretty spiffy helmet in the "Great War." For a "bump cap," the Legion Kepi would look sharp, neck scarf and all!
The Germans would, of course, have little spikes in the tops.
Office wonks, and other visitors, would get helmets with little propellers on them
:-)
