16.3.—(1) Service by a method mentioned in rule 16.1(1)(a)(i), (ii) or (iii), or (b)(i), shall be executed by a messenger-at-arms who shall–
(a)explain the purpose of service to any person on whom he executes service;
(b)complete a citation or notice, as the case may be, and a certificate of service in Form 16.3; and
(c)send the certificate of service to the pursuer.
(2) Such service shall be witnessed by one witness who shall sign the certificate of service (which shall state his name, occupation and address).
(3) Where service is executed by a method mentioned in rule 16.1(1)(a)(ii) or (iii), or (b)(i), and the document served is left in the hands of a person other than the person on whom service is to be executed, that document and the citation or notice of intimation, as the case may be, shall be placed in an envelope (bearing the notice specified in rule 16.4(2)) and sealed by the messenger-at-arms.
(4) A messenger-at-arms shall, when he executes service of a document, have in his possession–
(a)in the case of service of a copy of a principal writ, the principal writ or a copy of it certified as correct by the agent for the party whose writ it is, and
(b)where an interlocutor has been pronounced allowing service of the document, a certified copy of that interlocutor,
which he shall show, if required, to the person on whom he executes service.
(5) The certificate of service required under paragraph (1) shall include the full name and designation of any person in whose hands any document and the citation or notice, as the case may be, were left.
(6) In the application of this rule to service in a part of the United Kingdom furth of Scotland, reference to a messenger-at-arms shall be construed as a reference to a person entitled to serve Supreme Court writs in that part.