If a permissive parking sign indicates that it applies at particular times, or at particular times on particular days, a driver may park on the length of road, or in an area, to which the sign applies at a time, or at a time on a day, when the sign does not apply, unless—
(a) another parking control sign applies to the length of road or area; and
(b) the driver is prohibited from parking on the length of road, or in the area, at that time, or at that time on that day, under this regulation.