Guidance on how to manually calculate the Income Tax, National Insurance and student loan deductions due on the disguised remuneration loan charge has been published by HMRC on the Gov.uk website.
The loan charge arises on 5 April 2019 in the final pay period of 2019.
When you report your employee’s outstanding disguised remuneration loan balance you may need to use HMRC’s Basic PAYE Tools (BPT) to send an Earlier Year Update (EYU) submission.
You’ll need to calculate the tax, National Insurance and student loan deductions due. If your current payroll software product cannot perform these calculations for you, you’ll need to use the manual tax, National Insurance contributions and student loan tables.
See the guidance here