It turned out to be quite simple . For the 4 * 4 matrix layout (in portrait mode) , I had the bottom two with the vertical arrows (on the back of the panel) pointed upwards and for the top two , I had the panels 'upside down' ie with the vertical arrows (on the back of the panel) pointed downwards . The BBB config then needs to reflect the orientation. Connected this to Port 1 of the Octoscroller Repeated the same for Port 2 for the next set of 4 panels. I will post a picture of the panel layout and BBB config setup this evening and update when I have all panels together.