Thanks for the replies. Unfortunately no warranty! I think I'm just gonna replace the whole seat, will be easier and cheaper than trying to fix it! (In fact, I'm now kicking myself as someone offered me a pair of SRT6 seats a while back for £200!)

+fire, I have to admit that I was pretty concerned by the quick time that part of the seat heated up to an untouchable temperature - I was a bit worried the car was gonna catch fire, so I stopped out the front of a police station!!