69The instrument appointing a proxy and the power of attorney or other authority, if any, under which it is signed or a notarially certified copy of that power or authority- shall be deposited at the registered office of the company or at such other place within-the United Kingdom as is specified for that purpose in the notice convening the meeting, not less than 48 hours before the time for holding the meeting or adjourned meeting, at which the person named in the instrument proposes to vote, or, in the case of a poll, not less than 24 hours before the time appointed for the taking of the poll, and in default the instrument of proxy shall not be treated as valid.