Rubbing/Binding noise from OSR
 

Got a rubbing/binding noise from off side rear. Only appears when car is cold and brakes haven't been used much. At a recent service I mentioned it so they would have a quick look. The report back was that the rear disc was showing signs of slight corrosion which could cause the noise but had plenty of life in it if I could live with the noise. To be fair the noise was only slight but in the recent snow/cold snap it appears to be getting a bit louder.
Do you think that this is the likely cause or could it be something else although I would have thought they would have checked things like the wheel bearings etc. Car is a 07 Hawkeye WRX