The cable is available from any motorfactor that stocks FAI or QH, the cable is probaly corroding inside and has snaped strands so it's wirth replacing it outright. £25 so be al it costs at most.
tie a piece of string to the end of it and then pull it through, then the string will show you the route to fit it back in, also if the car is on ramps you can get your arm up in behind the engine