Giving of notices, etc
11 Where any notice or other written matter is required under the provisions of these regulations to be given or supplied by the committee (including any such matter to be supplied to a party for the purposes of a reference to which regulation 6 of these regulations applies) it shall be sufficient compliance with the regulations if such notice or matter is sent by post in a prepaid letter and addressed to the party for whom it is intended at his usual or last known address, or if that party has appointed an agent to act on his behalf in relation to the reference, to that agent at the address of the agent supplied to the committee.