Lawnflite 603 ride on

Has anybody else got a lawnflite 603 ride on tractor mower? I bought one brand new a few weeks ago,the first time i used it,i went over a manhole cover what is flush with the lawn,the turbo fan under the mower blade sucked the manhole cover up and bent the blade and smashed the fan,which has cost me £112 to replace,has anyone else had this problem,i have been running over the same manhole for 25 years with no problem with my westwood lawn tractor,i would have liked to have been informed on purchase that they suck manhole covers up,and do Lawnflite know of this problem,please reply to me by email [email protected],regards jim