Validity of service: procedural defects do not invalidate proceedings unless they cause substantial injustice that cannot be remedied. Defects in the name or description of a person in partner lists, petitions, summonses, notices or other proceedings do not render service invalid if the Tribunal is satisfied the service is otherwise sufficient; formal defects or irregularities do not invalidate proceedings unless a Member shows that substantial injustice has been caused and that such injustice cannot be remedied by an order of the Tribunal.