Provided nevertheless, and be it enacted, That any Term or Terms of Years which shall have been or may be assigned to attend the Inheritance in any of the Messuages, Buildings, Castles, Forts, Lines, or other Fortifications, Manors, Lands, Tenements, Hereditaments, and Premises, which shall be or become vested by virtue of this Act in the said principal Officers or their Successors, shall remain and be vested in the Trustee or Trustees, his, her, or their Executors, Administrators, or Assigns, to whom the same have been or shall be respectively assigned, and that it shall be lawful for the said principal Officers for the Time being to convey, surrender, or assign all or any of the Hereditaments and Premises which now are or hereafter shall be vested in them, and to direct all or any of the Hereditaments and Premises which shall hereafter be agreed to be purchased or taken by them to be conveyed, surrendered, or assigned to a Trustee or Trustees, for the Use of the Ordnance Department, or the Defence of the Realm, upon the Trusts to which the same shall or ought to be subject, in case from any Circumstance whatsoever it shall in the Judgment of the said principal Officers for the Time being be expedient so to do, any thing herein or in the said recited Acts contained to the contrary notwithstanding.