Noted Jon - thanks. What Lowrance units were you using your Point 1 with? Interestingly, the refresh rate on the Point 1 is the same as on the internal GPS of the head units these days, 10hz. I've only bought it for the compass/heading info really, so I may play around with the network settings and see if I can use the internal GPS for location data and only use the heading info from the Point 1 if mine is as hard to calibrate as yours was.
As for the switch panel - no idea. I bought the boat in September, so I don't know the history of the switch panel per se. I'm guessing it was fitted during the build and a lifetime of marina moorings and salt air have taken their toll on it. The rest of the under-dash hardware looks absolutely fine - no hint of corrosion anywhere else, so I suspect it's an isolated case. I'm sure these units are built to a price point.
Good idea about Yamaha lube, I'll give the exposed connections (and switch gear) a wipe over with it.