to bring or defend a claim rests with the company. So, if your client is a body corporate, you need proof that its decision to instruct you binds the entity and is not just the view of its instructing representative. You need to be sure too of the validity of the document; a forged consent is no consent. Failure to do this can be a breach of the warranty of authority and leave you with a material personal liability.
Authority can be provided through:
Note, you can take pre-action steps based on the authority of anyone with ostensible authority.
For further details, see the SRA Code of Conduct for Solicitors at paragraph 3.1 and the case of Rushbrooke UK Ltd v 4 Designs Concept Ltd [2022] EWHC 1110 (Ch).