(1) No such advertisement is permitted other than one—
(a)bearing the name or device of any person occupying the building; or
(b)referring to a specific event (other than the offering of named goods for sale) of limited duration, which is taking place in the building, for the duration of that event.
(2) No character or symbol on the flag may be more than 0.75 metre in height, or 0.3 metre in an area of special control.