Accounts for CT600

Quick question.  Years ago, I remember a few occasions where corporation tax returns were filed with final but unsigned accounts, where the accounts were not expected to change but for various reasons hadn't actually been signed.

I now have a situation where the directors want to file a CT600 early as it contains a repayment claim, but the accounts can't be signed off for a few weeks for various complicated reasons.  The accounts are final and have already been audited, so no further changes are envisaged.  However when I produce the iXBRL accounts, I need to put in a date of approval and a director's name otherwise I can't produce the accounts for filing with the CT600.

Is it possible (and permissible) to file the CT600 before the accounts are approved nowadays?