The company may sell, in such manner as the directors think fit, any shares on which the company has a lien, but no sale shall be made unless some sum in respect of which the lien exists, is presently payable, nor until the expiration of fourteen days after a notice in writing, stating and demanding payment of such part of the amount in respect of which the lien exists as is presently payable, has been given to the registered holder for the time being of the share, or the person entitled by reason of his death or bankruptcy to the share.