I would recommend to take the pads out and check the condition. If ok then you should clean all the built up dirt on the running surfaces between the pad and caliper with a file and then cover with copper slip. You will be shocked with the amount of hardened crud thats in there and the average garage will never do this. Then put copper slip on the contact surface on the back of the pads. Be very careful not to get any on the pads or disc as they will be contaminated and will have to be chucked.
I do this every 6 months to my brakes, back and front. After you have done them you can feel the difference in braking sensitivity. Much improved.
I would be suprised if they are still squeeling after this.