[Closed] chain comes off

does anyone else who ownes a boardman pro 2 x 10 have the same thing happen on there bike , if i change to big ring at the front and im more than halfway down the cassette the shain comes off the front ring over the crank arm side. stops & cables are adjusted correctly onyl thing im told is that there is such a massive diffrence between granny (27t) and big ring (42t) that the chain has to be long and in the case of changing gear it over throws the big ring grateful for your thoughts .