The test site is here:
www thesummerslam com/showdown/vlvshowdown html

As you can see, the whole site resizes/re-aligns when you click on the "Gallery" image in the bottom right of the screen

Sorry for the stupidity, but which part of the code do I need to amend?

This bit?
stage.scaleMode = StageScaleMode.NO_SCALE;
stage.align = StageAlign.TOP_RIGHT;       

Or this bit?
stage.addEventListener(Event.ENTER_FRAME,resizeTiltViewer);
function resizeTiltViewer(e:Event){       
    //example tiltViewer size and position values
    var tvWidth = stage.stageWidth/2;
    var tvHeight = stage.stageHeight/2;
    var tvX = stage.stageWidth/4;
    var tvY = stage.stageHeight/4;       
    ldr.x = tvX;
    ldr.y = tvY;
    var tiltviewer = Object(ldr.content)._app;
    if ( tiltviewer != null){
        tiltviewer.autoSize = false;
        tiltviewer.setSize(tvWidth,tvHeight);
    }   
}