BORING!
Each branch of the services has their niche. The RN move the booties around to good effect (as long as it's near some water), the AAC are good at making stuff go bang. If people have a problem with the way the SH Force do business, then 30 years downstream is a bit late to start raising the issue.
The RAF have the Puma, Merlin and mighty Wokka to complete the task and so it is up to them to decide their crewing.
In answer to the question do rotary need a crewman to navigate, my answer is definately no. It's a nicety, but I will say it's all very well two stick chimps flying it to point B, but how do they control a triple load pick up or load an internal wmik?
I'm not saying I (as a wokka crewman) am indespensible(I'd rather wave the pilots off for 3 hours IF) but you cannot utilise the aircraft effectively without a crewman. The Yanks, Aussies, Cloggies etc agree. They may call the people different names, but it's still a crewman.