Any land use activity existing on the effective date of this chapter which was previously authorized or approved by the Board of Trustees, Planning Board, Zoning Board of Appeals, Building Inspector or Code Enforcement Officer having jurisdiction to render such approvals may continue to be used in accordance with the terms and conditions provided incidental thereto; provided, however, that where such use would be permitted subject to less stringent controls under the terms of this chapter, then the terms of this chapter shall prevail. Where the terms of this chapter are, however, more restrictive, then such use shall, for purposes of any subsequent modifications, enlargements or changes in use, be subject to the provisions of this chapter as if such uses were new uses.