Hi James Harvey,
If paid by internet banking it can take up to 7 working days to process to your Self Assessment account.
To pay the balance from your HICBC through your tax code the Self Assessment for 2022/23 had to be received by 30 December and the balance due would need to be less than £3000.
You would also need to have a PAYE source with high enough income to collect the balance.
Your tax code can be updated going forward to include the HICBC so you pay tax at source.
You will still need to complete the Self Assessment at the tax year end but should not have a large balance to pay as tax paid at source on HICBC.
To review/update your tax code you will need to contact HMRC:
Self Assessment: general enquiries
Thank you.