56Execution of documents: presumption of validity of officer's signatureE+W+S
(1)This section applies to a document—
(a)by which a contract is purportedly made, varied or discharged by or on behalf of a registered society, and
(b)which is purportedly signed by a person holding an office in the society.
(2)The signature is presumed, unless the contrary is proved, to be the signature of a person holding that office at the time the signature was made.