(1)A designation under section 11 is subject to such limitations as may be specified in the designation.
(2)A limitation specified under subsection (1) may, in particular, relate to—
(a)the functions that are exercisable by virtue of the designation, or
(b)the purposes for which those functions are exercisable.
(3)A designation under section 11—
(a)may be permanent or for a specified period,
(b)may (in either case) be withdrawn, and
(c)may be varied.
(4)The power to designate, or to withdraw or vary a designation, is exercised by the Director of Border Revenue giving notice to the official in question.
(5)The Director may designate an official under section 11 only if the Director is satisfied that the official—
(a)is capable of effectively carrying out the functions that are exercisable by virtue of the designation,
(b)has received adequate training in respect of the exercise of those functions, and
(c)is otherwise a suitable person to exercise those functions.