85Certain unregistered leases valid, but not rights of

85 Certain unregistered leases valid, but not rights of purchase or renewal under them (1) A registered lease is subject to any prior unregistered lease, or agreement for a lease, for a term not exceeding 3 years. (2) No right or covenant to purchase the freehold or to assign the reversionary interest of the lessor contained in any lease or agreement, and no right or covenant to or for the renewal of any lease or agreement, shall be valid as against any subsequent purchaser of the reversion, lessee, mortgagee or encumbrancee unless the lease or agreement is registered.