That's a classic failed stator you have there with three toasted coil windings shorting to chassis ground at the output cable. Middle for diddle seems like a good call for the replacement and it's a simple job the average 7 year old girl could do at the kerb side without breaking a finger nail. You'll now be wondering what all the stator fuss and hype is about. My second stator failed at 58,402 miles last November and I too opted for JMP's offering of their £99 stator (part number 7001810, might be a different number for the SC64) ordered from Brooks Barn on a Friday, delivered and fitted on a Sunday in 1½ hours which included removal of rear rack to access the stator/RR connector, displacing the Heed engine bars to access the stator cover and a tea break. I've put 5,000 miles on that JMP stator now and it's doing what it does keeping the battery topped up with similar numbers to yours.
Happy days