Section 8 Leases may be granted at diminished rent.
Notwithstanding any prohibition contained in any deed of entail against granting leases unless such leases are without diminution of rental, it shall be lawful for any heir of entail in possession of an entailed estate to grant leases for such period as it may be otherwise competent for him to do, at a fair rent.
Provided, that it shall not be lawful for such heir to take any grassum or other consideration for granting such lease other than the rent; and if the rent shall be less than a fair rent, or if any such grassum or consideration shall be taken, such lease shall be null and void.