No mortgage etc. to be created without consent of parties after execution of agreement for sale.

No promoter shall, after he executes an agreement to sell any flat, mortgage or create a charge on the flat or the land, without the previous consent of the persons who take or agree to take the flats, and if any such mortgage or charge is made or created without such previous consent after the agreement referred to in section 4 is registered, it shall not affect the rights and interests of such persons.