Received credit note for expenses in previous financial year after Q4 vAT declaration. How to record this?

Don't you always have to enter it in Q1/2023? Your vAT declaration is closed, there's nothing you can do about that. So I think it should be entered in the next quarter.

If I'm not mistaken, you have to enter it in previous year's accounts, but choose January 2023 as the 'fiscal date'. That way, the 'cost' (refund) will still be in previous year's accounts, but you can sort out the vAT part this quarter.