Company registration treats prior constitutive provisions as registered memorandum and makes the Act applicable, with specified exceptions. Registration under this Part treats existing statutory provisions and the company's constitutive instrument as if incorporated into a registered memorandum and articles, and applies the Act to the company, members, contributories and creditors as if formed under the Act, subject to exceptions (optional Table F adoption, share-numbering non-application, and contributory liabilities for pre-registration debts in winding up). The Act's rules on converting unlimited to limited companies, altering nominal capital and making portions of capital uncallable on winding up apply notwithstanding contrary instruments, while prohibiting alteration of mandatory memorandum provisions and preserving pre-existing powers to alter constitutions except as limited by the Act.