The Helicopter Museum at W-s-M, is quite a place. I went a while back and the Rotodyne jets were in a box ready to be placed on display. like you say Straight Up, huge.
(Anti-torque not mentioned in original question, steering is.)
I think you'll find that in the hover and in forward flight, yaw was controlled by differential propeller pitch. Once in forward flight the aerodynamic surfaces would be come more effective.
Strangely enough, Westland took over Fairey and despite commercial interest, shortly afterwards the project was cancelled.