Validity of proxies
29A vote given in terms of an instrument appointing a proxy shall be valid notwithstanding the previous death or insanity of the principal or revocation of the proxy or of the authority under which the instrument was executed, provided that no intimation in writing of such death, insanity or revocation as aforesaid shall have been received by the Company at its head office four hours before the commencement of the meeting or adjourned meeting at which the proxy is used.