If the camera is on a tripod i would do it this way.
Video track 2 - shot of scene without pferformer (really needs to be a low movement b ground for best result).
Video track 1 - performer on ropes. Use brightly coloured rope, a colour that does not appear much in the scene. Many ropes are bright blue or orange.
Key track 1 to the rope colour - ropes become transparent allowing background on track 2 to show.
Not somethnig i have done but have removed similar things in this way.