Corrosion on rear coil springs. How soon should I replace?

[kissenger]

My car (2011 Hyundai ix35) went in for its MOT today. It passed but the technician noted corrosion on one of the rear coil springs. Is this something I should worry about immediately? I'd rather wait 6 months if I can and then replace them both.

 

[kissenger]

It was an advisory. I'm picking up the car after work, so I'll ask for more detail at Hyundai. From what I've read though unless it's an outright fail it's usually not urgent.

 

[kissenger]

They said it was just 'surface rust' when I collected the car, so I'll leave it, but makes me wonder why they even bother putting it on the MOT.