Colibri.
The question of why Pilots should wear helmets when pax don't can be very simply addressed - There is a hell of a lot more stuff for us to smack our heads off then for the pax - Switches / panels / rotor brake levers etc. And that's before you consider the bird-strike / visor argument.
However: i agree with your position that there is not a significant safety case for helmets in N-Sea ops (although i think they should be made available to those that want to wear them).
OH