A designation under section 3 is subject to such limitations as may be specified in the designation.
A limitation specified under subsection (1) may, in particular, relate to—
the functions that are exercisable by virtue of the designation, or
the purposes for which those functions are exercisable.
A designation under section 3—
may be permanent or for a specified period,
may (in either case) be withdrawn, and
may be varied.
The power to designate, or to withdraw or vary a designation, is exercised by the Secretary of State giving notice to the official in question.
The Secretary of State may designate an official under section 3 only if the Secretary of State is satisfied that the official—
is capable of effectively carrying out the functions that are exercisable by virtue of the designation,
has received adequate training in respect of the exercise of those functions, and
is otherwise a suitable person to exercise those functions.