Nothing contained herein will require any change in the overall layout, plans, construction, size, or designated uses of any development, building, structure or part thereof, for which the official approvals and required building permits have been granted before the enactment of this Zoning Code, the construction of which, conforming with such plans, will have been started prior to the effective date of this Zoning Code and the completion thereof carried on in a normal manner within the subsequent six-month period, and not discontinued until completion, except for reasons beyond the developer’s control.