Yes, I know about XCP, but I have a cupboard full of ACF50. I've used it successfully for years, so I'm happy to run these stocks down first. The muc-off is to help me wash off the salt, before I reapply the ACF50.
It's a pain, but in winter I spend a couple of hours washing my bikes down, blow drying and reapplying corrosion protection after each ride. They get to spring without corrosion. But previous bikes have always been less than a few years old. Hope the Norton copes as well. (My driveway is pretty clean too!)