I took delivery of mine in February this year, 4 months old with 300 miles on it, and have been riding mine occasionally since February this year and so it has seen salt a few times, although I always rinse it of with the hosepipe before parking it up. There is some light marking on the "shiny" parts of the wheels which has **ssed me off a bit. It wouldn't be too bad if you could get at the areas concerned, but in reality the only way is to take the wheels off and remove the discs to achieve this.
I would describe the corrosion on mine as light marking. Based on my description, do you think yours are probably considerably worse than this?