(1) An advance care directive—
(a) must be in writing in English; and
(b) must include the full name, date of birth and address of the person giving it; and
(c) subject to subsection (2), must be signed by the person giving it; and
(d) must be witnessed and certified in accordance with the requirements set out in section 17.
(2) A person may sign an advance care directive at the direction of the person giving the directive if the person signing—
(a) is an adult; and
(b) is not a witness to the signing of the document.