7. Any order, notice or decision made, given or taken or any other thing done, before 1st April 1965 under any provision of Part V of the Public Health Act 1936 or Part IX of the Public Health (London) Act 1936 by or to any authority in Greater London, or in the urban districts of Potters Bar, Staines or Sunbury-on-Thames or an officer of any such authority in relation to any person, premises or article shall have effect on and after that date as if it had been made, given, taken or done by or to the authority which is the local authority for the purposes of the said Part V in relation to the person, premises or article, or, as the case may be, an officer of that authority, and in the case of any order, notice, decision or other thing made, given, taken or done under any provision of the said Part I X,as if it had been made, taken, given or done under the corresponding provision of the said Part V.