reg 13 Date of service
Unless the contrary is shown, a document served on a person (otherwise than personally) shall be assumed to have been served— (a) in the case of a document sent by post from the United Kingdom to an address within the United Kingdom, on the fifth day after the day on which it was despatched; (b) in the case of a document sent by post— (i) from the United Kingdom or Germany to an address within Germany, or (ii) from Germany to an address within the United Kingdom, on the tenth day after the day on which it was despatched; (c) in the case of any other document sent by post, on the tenth day after the day on which it was despatched; (d) in the case of a document served by DX, on the fifth day after the day on which it was left at the addressee's DX box number or despatched; (e) in the case of a document served by fax, electronic mail or other electronic means, on the day after it was transmitted; and (f) in any case, on the day on which the addressee responds to it if that is earlier.