When I worked at Redhill, over 20 years ago now, there was a small hangar next door, belonging to Cierva. They were working on a twin piston Helicopter called the Grasshopper, it had contra rotating main rotors, and large tail booms with no tail rotor.
I saw it flying once, and it looked very smooth. I assume they ran out of money, like a lot of projects, but I believe it did actually fly at Farnborough.