(1) The maker of the list of documents must certify in the list of documents that —
(a) the maker understands the duty of disclosure; and
(b) to the best of the knowledge of the maker the duty has been carried out.
(2) In the case of a list served on behalf of a company, firm, association or other organization the certificate referred to in paragraph (1) must be made by the person identified in rule 28.7(6)(a).
(3) If it is impracticable for the maker of the list of documents to sign the certificate required by paragraph (1), it may be given by that person's legal practitioner.
(4) A certificate given by the legal practitioner must also certify —
(a) that the certificate is given on the instructions of the maker; and
(b) the reasons why it is impractical for the maker of the list of documents to give the certificate.