(c) Within a partial enclosure that includes an overhead cover and more than two walls, the following shall apply:(i) At least 25 % of the total wall area is completely open; and(ii) At least 30 % of the remaining wall area is open and unrestricted.In the case of balconies, verandas or awnings, at least 20 % of the total of the side, back and front wall areas shall remain open and unrestricted.A label with the following information in 5 mm font shall be displayed on or adjacent to the entry door of caravans:WARNING — IF FITTING AN ANNEX CONTACT A GASFITTER TO ADVISE ON THE VENTILATION REQUIRED FOR SAFE OPERATION OF GAS APPLIANCES.