27.— (1) A direction under this Part shall—

(a) be in writing,

(b) specify the date from which it is to operate and the time within which the requirements specified in the direction shall be complied with, and

(c) subject to subsection (2), be addressed to the person concerned.

(2) Where the name of the person concerned cannot be ascertained by reasonable inquiry any direction may be addressed to “the occupier” or “the person in charge” as the case may require.