4.5.—(1) This rule applies where—
(a)the person to be served—
(i)has given a document exchange (DX) box number, and
(ii)has not refused to accept service by DX; or
(b)the person to be served is legally represented in the case and the representative has given a DX box number.
(2) A document may be served by—
(a)addressing it to that person or representative, as appropriate, at that DX box number; and
(b)leaving it at—
(i)the document exchange at which the addressee has that DX box number, or
(ii)a document exchange at which the person serving it has a DX box number.