it doesn't matter where you bought them from or how much you paid for them. if the ghds are faulty, send them straight back to GHD with a covering letter explaining the fault. they don't need to be in the original packing and you don't need the receipt. if there's something wrong with them there's something wrong with them, end of.
ring this number first: 0845 3301133
and explain the problem, then they'll give you an address to send them off to.
i've been using GHDs for over 4 years now, had the first batch that went out, which blew up, and over the years have sent back 3 sets cos all have had problems. but i still wouldn't use anything else. you'll find they are really good with returns and will generally just send you a new set in the post with a letter appologising for the problems you've had. x