A notice, order or document in a proceeding commenced against partners in the firm named under rule 4.33 may be served on or given to the partners and the firm by—
(a) serving it on any one or more of the partners in any manner in accordance with section 140(1)(a) of the Act; or
(b) sending it by post to the firm at its last known business address; or
(c) sending it by electronic communication to the firm at its last known address for receipt of electronic communication; or
(d) leaving it at the firm's usual or last known business address with a person on the premises who is apparently at least 16 years old and apparently employed there.