The fixing method, which is the same for all panels, uses a uniquely designed extruded aluminium fixing clip. The clip has a small lip on the back which is inserted into the receiving groove at the top of the panel. The panels are then fixed to the supporting frame by means of stainless steel fasteners having regard for the chosen panel/panel joint dimension (1-5mm.) via a spacing guage. This fixing method will permit the panels to freely expand and contract.