Hello Rory

Sorry to hear of the cable failure on the Nel Tornado coil.
I have dropped it off at an electrically minded friends just now....
I think this is always worth the effort as a 'last ditch attempt at reair. I can understand some official repair sources being reluctant to deal with these faults as they invariably necessitate fairly intrusive work just to investigate the cause with the probability that a repair is not possible
Hopefully your pal will meet with success

Keep us informed please - Regards ss47
Edit:- I should have added that from my experience (of attempting a similar repair), following making good the fault, producing an effective grid-screened insulation of the repair proved very difficult to achieve! Mine failed within 6 months

Good Luck
A disservice is no service at all.