rear brake woes. :(

[Seabass]

Much to my dismay I've spent much of today trying to figure out why I had no pressure in my rear brake after swapping out old brake pads for new. I eventually found that the upper sliding bolt is bent or not running straight, due to the caliper mounting ear (if that makes sense) which the sliding bolt goes through is slightly bent! Are these things made of putty? I cannot remember a single occasion where I feel I've placed enough force against the sliding bolts to bend the caliper like that.

Does anyone know how I can straighten it? Or is it a case of new caliper?