Except to the extent to which a member of a company agrees in writing at any time to be bound thereby, and anything to the contrary in the memorandum or articles notwithstanding, the member shall not be bound by any alteration made in the memorandum or articles of the company requiring him on or after the date of the alteration to—
(a)
take or subscribe for more shares than he held at the date on which he became a member ;
(b)
increase his liability to contribute to the share capital of the company; or
(c)
pay money by any other means to the company.