The employee works 4 days a week, Tuesday to Friday, full days.
For your part-time staff member, this equates to:
2023
4/5 or 80% of 9 bank holidays = 7.2 days = 7.5 days
9 bank holidays this year due to the coronation.
They are entitled to be paid for 7.5 bank holidays in the holiday/calendar year.
Whether they normally work them or not.
So starting from 1 January, they would be paid for the first 7.5 bank holidays in the year:
Fully paid and not working
2 January, Good Friday, Easter Monday, 1 May, 8 May, 29 May, 28 August
Half paid and not working (unless they use part of their holiday entitlement to make up the difference)
25 December
Not paid and not working (unless they use part of their holiday entitlement to make up the difference)
26 December