Invoice with outstanding Balance without Log Payment Option

Good morning, I am trying to log a payment against Invoice No. 000071 dated 13.11.2013 which shows an
outstanding balance of £715.000, the amount I wish to log, but there is no log payment button?

Please can you retry now? There was a lock on the invoice due to it having multiple Credit Notes and being reconciled in a VAT return. Should be fine now!

Thanks very much all done now.