27. Nothing in paragraph 20 or 26 shall preclude the promoter from submitting at any time, or from time to time, but in no case less than 28 days before commencing the construction of any specified work, a new plan in place of the plan previously submitted, in which case the provisions of those paragraphs shall apply to, and in respect of, such new plan except that the reference in paragraph 26 to 42 days shall be treated as a reference to 21 days.