
As Christmas Day and New Year’s Day fall on weekends, neither is a bank holiday and therefore substitute days are used instead.
So Tuesday 27th December 2022 is the official bank holiday substitute for Christmas Day and Monday 2nd January 2023 the official substitute as New Years is a Sunday.

Do Bank holidays have to be paid?
Bank or public holidays do not have to be given as paid leave.
An employer can choose to include bank holidays as part of a worker’s statutory annual leave of 5.6 paid weeks (capped at 28 days annually).
Some employers may contractually provide additional bank holiday pay entitlements. The contract may state which days are specifically included such as Christmas Day and New Years. Of course the Christmas Day 2022 is not an official bank holiday, neither is New Year’s Day 2023 as they both fall on a Sunday.
Employers may need to decide what policies they implement and communicate with their employees and workers.
Reporting PAYE information in real time when payments are made early at Christmas

As part of the October 2022 employer bulletin, HMRC are reminding employers of the permanent easement on reporting PAYE-information in real time which has been in place since 2019.
Some employers pay their employees earlier than usual over the Christmas period. This can be for a number of reasons. For example, during the Christmas period the business may close, meaning workers need to be paid earlier than normal.
If you do pay early over the Christmas period, report the normal (or contractual) payday as the payment date on the Full Payment Submission (FPS) and make sure that the FPS is submitted on or before that date.
For example, if you pay on Friday 16th December 2022, but the normal (or contractual) payment date is Friday 30th December 2022, report the payment date on the FPS as 30th December 2022 and make sure the submission is sent on or before 30th December 2022.
Doing this helps protect an employees’ eligibility for Universal Credit, as reporting the payday as the payment date may affect current and future entitlements.
The overriding PAYE reporting obligation for employers is unaffected and remains that an employer must continue to report payments on or before the date the employee is paid, that is their payday.
Having to work Christmas and New Year?

ACAS have guidance on employment rights for those working during the Christmas season, for the PAYadvice.UK article and links see:
PAYadvice.UK 23/10/2022 updated 27/12/2022