(b) the person has the written consent of the persons whose human reproductive material was used to create the embryo, dated before the coming into force of these Regulations, stating that if the embryo is not required for the purpose for which it was created, it may be used for the purpose of providing instruction in assisted reproduction procedures, improving assisted reproduction procedures or other research, as the case may be, unless those persons have already consented to that use as the donor of the embryo.