It was like the Black Hole of Calcutta down there!
The cable is held well away from the steering column by a zip tie that holds it to part of the cable loom.
Interestingly the fraying was caused by the cable exiting the sheath through a metal ferrule at a non-optimal angle so that as the cable pulls open the throttle it rubs on the loert lip of the ferrule,
the wider the throttle opening the more it rubs. The hole in the ferrule is noticably oval. A total of 4 main strands had failed, about 40% of the total.
The solution requires the bracket holding the end of the cable outer and which is bolted to the inlet manifold is re-angled so the cable doesn't rubthe edge of the ferrule. I think a 1.5mm thickness washer under the rear mount may do this. More to do!
