In the event that the applicant has failed to commence construction within six months after such permit has been issued, or failed to proceed with construction, once commenced, in accordance with construction time table commonly prevailing in the construction industry, and subject to the Board’s discretion as to the reasonableness of construction delays or fails to conform to the provisions of the development plan, and supporting data finally approved by the Board, and upon the basis of which such improvement location permit for the special exception was issued, said Board may upon its motion or upon the written petition of any aggrieved person at a public hearing, require the applicant to show cause why the Board’s order should not be withdrew and the improvement location permit for the special exception be revoked.