..........But if you look at
this picture they are using a shaft drive system for the prerotator.
You can see a shaft running from the rubber prerotator drive wheel (belt drive, whatever) to the front of the engine to a small 90º gearbox. From there, through a telescopic shaft to the rotor head.
I have considered doing the same thing for my next machine. I saw a gyro at Mentone years ago that used the lower unit gears from an outboard to make the 90º turn, but I'm sure that a small gearbox could be found off-the-shelf. It should eliminate the friction from the teleflex cable rubbing inside the sheath..........