The front yard regulations shall apply to each street side of a corner lot and the Zoning Administrator shall designate the front yard on a corner lot. For corner lots platted or of record prior to March 19, 1959, the side yard regulations shall apply to the longer street side of the lot except in the case of reverse frontage where a corner lot fronts a different street than the lots to the rear of such corner lot. In this case, there shall be a side yard on the longer street side of the corner lot of not less than fifty percent of the front yard required on the lots to the rear of the corner lot, and no accessory building on said corner lot shall project beyond the setback line of the lots to the rear; provided this regulation shall not be so interpreted as to reduce the buildable width of the corner lot facing the intersecting street to less than 28 feet or prohibit the erection of an accessory building.