I had new windows fitted in december 09 and one is now cracked from one corner across one the small operner , the guy who fitted them said that he will replce it at cost as there no garentee ? Then said that pilkington glass is only garenteed for 2/3 years on misting wich dosent sound right to me . its only the new frames with a 10year warrenty, now i am wondering if the right glass has been fitted how can i tell?