Your first port of call, contact Peugegot 0845 200 1234, or Google their EMail address, give them the details in full regards you car, Reg / Milage / Chassis No/ On your V5 ( Log Book) where the car was bought, if need be take a photo of the seat if possible, I would say the the seat is not fit for its purpose & is faulty, the seat should have lasted longer than this, I would not go for a re-weld as this seat gets the most use, Customer Service is the department you want when you ring, the Depollution will more than likely be a filter that requires changing, lastly, I would not take it to a Peugeot dealer only to get the seat sorted Re/ what I have advised, If you are worried about the Warrantee, as long as you use a VAT reg Garage & use genuine peugeot parts the warrantee holds, regards the seat, I wopuld not offer to pay anything toward the cost.