I managed to resolve this, no need to open the console.
Stand xbox vertically and with front facing you
Through the vent at the top with a small screwdriver i kept turning the fan slightly until i could see a group of black cables clipped together through a gap in the fan blades. (Just right of centre at the front, nearest to you)
One of the cables was raised out of the group so i pressed down firmly on it and it is no longer catching the fan blade, been perfect since.
You may need a flashlight to shine into the vent
Hope this helps