3. Subject to the following provisions of this Order development within the development area in accordance with proposals approved by the Secretary of State under section 148(1) of the 1980 Act (not being development for which permission under the 1971 Act is granted or deemed to be granted otherwise than by this Order) is hereby permitted subject to such of the limitations and conditions set out in articles 4 to 6 of this Order as are applicable to that development and subject—
(a)to the development being begun within the period of five years beginning with the date on which the proposal for such development is approved by the Secretary of State or such other period (whether longer or shorter) beginning with that date as may be specified in the proposal as approved;
(b)where the development consists of or includes the erection, extension or alteration of any buildings, and is not to be carried out by the development corporation, to the approval by the corporation of the siting, design and external appearance of the buildings, means of access, provision for vehicle parking and for loading, unloading and storage of vehicles and containers, storage of materials in the open and landscaping of the site; and
(c)where the development consists of or includes the formation, laying out or alteration of a means of access to any highway used by vehicular traffic or the laying out of a new street, and the development is not to be carried out by the development corporation, to the approval by the corporation of detailed plans thereof.