Upon the bankruptcy of the proprietor of any lease under this Act subject to one mortgage only or to several mortgages if owned by the same person, the Registrar, on the application in writing of the mortgagee or his or her transferees accompanied by a statement signed by the Official Receiver refusing to accept such lease, shall enter in the Register Book a note of the refusal; and that entry shall operate as a foreclosure and as a transfer of the interest of the bankrupt in the lease to the mortgagee or his or her transferees; and, if he or she or they neglect or refuse to make such application as aforesaid within twenty-one days after notice in writing in that behalf from the lessor or his or her transferees has been served on the mortgagee or his or her transferees by being given to him or her or them or by being sent through the post office by a registered letter directed to him or her or them at his or her or their address as stated in the mortgage or transfer of the mortgage, the Registrar, on the application in writing of the lessor or his or her transferees to be registered as surrenderee or surrenderees of the lease accompanied by such a statement as aforesaid and proof of such neglect or refusal, shall enter in the Register Book notice of such statement and of the neglect or refusal; and that entry shall operate as a surrender of such lease discharged from the mortgage or several mortgages aforesaid, but without prejudice to any action or cause of action which previously has been commenced or has accrued in respect of any breach or non-observance of any covenant expressed in the lease or by law declared to be implied in the lease.