I have an R50 model Mini and recently it has started making a loud metal on metal sound when I touch on the brakes. It seems to come from both sides of the car at the front. It doesn't do it all the time but is there the majority of the time, mainly when the car is warm. It started the day I cleaned it, but I've looked and can't see anything around the wheel or brake pad that could be causing it? The brake pads also have a decent amount of "meat" left on them. Any suggestions welcomed.