Hi, This last few days I have noticed a grating noise in my steering, it is not there when I first start the car, It seems to appear after driving a while. I came to notice it when parking up both last night & tonight. I can only describe it as 2 pieces of metal rubbing together, there is no clunking or squealing, just this rubbing/grating noise. Do you think it is anything to worry about? Thanks in advance.