I have a 1960's detached house with an integral garage, I want to extend the garage forwards by 3 feet in order to butt up to the front elevation of existing porch (this will also increase the width of the porch by 4 feet), I know the permission document says permission is needed if you want to extend the 'principle elevation'..............but I'm not extending it, I'm butting up to what is already there aren't I ???