No member of a recognised stock exchange shall in respect of any securities enter into any contract as a principal with any person other than a member of a recognised stock exchange, unless he has secured the consent or authority of such person and discloses in the note, memorandum or agreement of sale or purchase that he is acting as a principal:
     Provided that where the member has secured the consent or authority of such person otherwise than in writing he shall secure written confirmation by such persons of such consent or authority within three days from the date of the contract:
     Provided further that no such written consent or authority of such person shall be necessary for closing out any outstanding contract entered into by such person in accordance with the bye-laws, if the member discloses in the note, memorandum or agreement of sale or purchase in respect of such closing out that he is acting as a principal.