17.3.—(1) Service may be effected via a document exchange where this rule applies.
(2) This rule applies if—
(a)a person has given a numbered box at a document exchange as that person’s address for service;
(b)a document exchange box number is inscribed on the writing paper of a party who acts in person or on the writing paper of a solicitor who acts for a party and the party or solicitor has not indicated in writing to the person serving the document that he or she is unwilling to accept service through a document exchange.