not heard of this before, mine are ok but i've only done 20k, I doubt you will get much joy with Nissan but worth a try, I'm sure it could be repaired though
I've just bought another car and there was a slight tear in the side panel on the seat, the garage took the seat out and a guy in Queensferry replaced the panel, you would never know it had been done !
shoot Mondo@Hide N Seat a pm, i'm sure he could give you some advice