It would be the same if she was there o Mondays as the majority of bank holidays fall on this day. It is normal practice, my son's nursery is the same
I think this is fairly normal. Our nursery has it in their contract that they will charge for bank holidays as the majority of people are paid for bank holidays and so their staff will be too.
Pretty sure they shouldn’t be charging if they’re closed? Our childminders don’t anyway x