23. Effect of alteration of articles on company's members
(1) A member of a company is not bound by an alteration to its articles after the date on which he became a member, if and so far as the alteration—
(a) requires him to take or subscribe for more shares than the number held by him at the date on which the alteration is made, or
(b) in any way increases his liability as at that date to contribute to the company's share capital or otherwise to pay money to the company.
(2) Subsection (1) does not apply in a case where the member agrees in writing, either before or after the alteration is made, to be bound by the alteration.