Where abouts do you keep your hair straightener? As it may be because its cold or has condensation inside it. This may sound funny but you actually shouldnt keep your GHD in the bathroom cause they can get cold and dont like it, or if u want to keep it in the bathroom then wrap it in a towel. This may fix the problem. If not then call GHD and you may be able to get a replacement. Hope this helps :)
For curling, place a section of hair between the plates closest to the scalp, clamp the plates, and turn styler through 180 degrees while holding the end of the strand. Pull styler through the hair slowly, always maintaining the 180 degree turn--it helps to slightly tip the nose of the styler downward, careful not to let the hair fall out. It also helps to pull the strand forward when trying to curl hair at the back of the head.