Nothing herein contained shall require any change in the overall layout, plans, construction, size or designated use of any development, building, structure or part thereof for which official approvals and required building permits have been granted before the enactment of this Zoning Code (Ordinance 1420, passed February 28, 1966), the construction of which has been started within three months after the effective date of this Zoning Code. (Ord. 1420. Passed 2-28-66.)