Every consent which, on the behalf of any heir of entail being under age, or subject to any legal incapacity, whose consent has been or is or shall be required under the said recited Act, has been or shall be given by any tutor or curator or other legal guardian duly authorized to consent in terms of the said recited Act on the behalf of such heir of entail shall be deemed and taken to be and shall be valid and sufficient, except in any case of application for disentailing, without the concurrence of such heir of entail, and without any consent to or approval of the actings of such tutor or curator or other legal guardian by such heir of entail; but the consent of such curator or other guardian on behalf of such heir of entail, in terms of the said recited Act, shall not in any future application under the said recited Act or this Act, or in any application under the said recited Act not yet finally disposed of (unless in any case in the circumstances of which the Court shall be of opinion that the consent of the tutor, curator, or other legal guardian alone is sufficient), be received or acted on where such heir of entail, being of sound mind, and above the age of fourteen years, shall, in the course of the application wherein such consent may be tendered, enter appearance and oppose the reception of such consent, which such heir of entail is hereby authorized to do.