Cenvat credit

Dear All, I have filed service tax return for the Period oct13 to Mar14 in that return I have not Availed CENVAT credit on service tax paid on Security Charges(Service tax amount 77122 for the period 1/4/2013 to 31/03/2014). Now while finalising accounts, I came to know that since this was allowable as credit against output service. Whether I can avail and Utilise this CENVAT credit of Rs. 77122 (which earlier not availed )in the return of Apr14 to Sep14.