From the Government's direct.gov.uk site
"Public and bank holidays
You do not have a statutory right to paid leave on bank and public holidays. If your employer gives paid leave on a bank or public holiday, this can count towards your minimum holiday entitlement. There are eight permanent bank and public holidays in England and Wales (nine in Scotland and ten in Northern Ireland).
If you work on a bank or public holiday, there is no automatic right to an enhanced pay rate. What you get paid depends on your contract of employment.
If you are part time and your employer gives workers additional time off on bank holidays, this should be given pro rata to you as well, even if the bank holiday does not fall on your usual work day."
Many folk think they are automatically entitled to extra pay when working overtime or on Bank Holidays but it is not the case, yir pal should check her contract and terms of employment.