HICBC / BIK (P11d) on Self Assessment - pay tax separately?

My partner and I have claimed Child Benefit in the 23/24 tax year, and understand we need to complete a self assessment in order to pay the HICBC, so we have kept the money aside in order to pay tax. However, my partner also receives benefit in kind from his employer (medical insurance) which is declared on his P11d and he usually pays the tax on this through his tax code. We would like to pay the HICBC by bank payment, but when completing the self assessment, it requires the benefit in kind to be declared, and includes the tax owed on the BIK in the final tax calculation. Is there any way we can pay the tax for the HICBC via bank payment, and keep the BIK tax paid by his tax code? Or do they both have to be paid in the same way? Ideally we'd like to keep his personal tax for the BIK separate from the HICBC as we have saved the tax for this as a couple.

Hi Abk07,
If the 2023/24 return is filed before the 30th December 2024, and the payment for the HICBC is present on your partner's statement, we may be able to code out the remaining BIK amount.
To allow us to confirm this, contact us by webchat or phone via Self Assessment: general enquiries.
Thank you.