Hi John, Took about nine inches off the end which included the zigzag piece internal to the switch handle. It certainly was badly marked from the outside, as the internal handle design forces it into the tight zigzag. Stripped the outer sheath off and looked at the blue and brown wires. No sign of damage at all. Tried to pull the conductor out but could not.
I decided to just replace the whole cable as I had a spare and I have to say that so far all is well, and having changed the position of the switch handle both off and attached to the mower handle, the motor started every time so I suspect your answer was spot on even though I have so far not traced the exact faulty bit of cable.
Thanks for taking the time to reply.
Lewis
April 2009