Flexible with a stainless end and thumbscrew. Rosette knob other end. On a loaner scope, came back with stripped thread rendering the cable useless. :-(
Malcolm, your flexible control might be repairable.
I had a similar issue with one of mine. I found a slightly larger diameter locking nut. I then drilled out the stripped thread and tapped in a new thread for the larger lock nut. Good as new.
This might be an option for you. The cost would be less than a new one, even if you had to buy the thread tap. The only others tools needed would be the right sized drill bit and a small spanner to turn the thread tap.