I remember the City home game in Division 2 in 1974 with United well. Their fans were given the whole of the bob bank and pretty much filled it as well (10000 ish ?). Some of them spent most of the game demolishing the walls at the back and around the floodlights and trying to lob the resulting ‘spare’ breeze blocks and bricks into to Grange End. Only to be returned with interest of course. United won by the way.