Hi, I'm redoing an ensuite and ideally would fit a corner toilet. It's on an outside wall but there's an existing 4" waste 500mm along the wall from the corner, inside. Do you think it's viable to connect to that existing waste using a flexi waste and angles, inside? Or using a 45 degrees and two 90's? Or do I really have to drill a new 4" hole right next to the new corner toilet and fill in the old one? What do you think? Thanks.