Nice to see the interest in this...but please note Rotodyne had no R in the middle!
Anyway,three follow up points
1) When the Helicopter Museum collected a test blade from Aston Down airfield many moons ago they also collected a number of tipjet silencer units,which had been trialled on the blade(attached to a whirl tower). The story goes that these noise tests were actually connected to Rolls Royce work silencing the noise levels of the Viper engines on the HS125 corporate jet but previously had demonstrated significant noise reduction in the Rotodyne application. Certainly the evidence is that by the time of the cancellation the noise issue was much less of a show stopper.
2) Physically moving the blade was and still is a major challenge.It is so heavy as to require about 8 -10 strong men to lift it.....even moving one of the blade arms is a six man job.....so weight was a big issue. Today with modern composites it would be so much more viable.
3) There was another factor in the early 1960s that led to cancellation and that was that when Westland took over Fairey and the Bristol helicopter division,they had three" heavy lift" helicopters on their books but only one had any orders,the Belvedere. As they couldn't afford to develop all three ,the Rotodyne and the Westminster were abandoned. Big mistake in retrospect as the Belvedere never amounted to much( another story of poor government investment when you look at the Chinook story ) and the Westminster also could have been very successful ......perhaps subjects for new threads at some other time?