I get childcare vouchers and I understand that my employers will carry on providing the vouchers when I'm on statutory maternity pay. I'm not planning on going back and I will get a payment for my holiday at the end of my notice period. I was wondering whether they will be able to deduct 9 months of childcare vouchers out of my holiday pay when I quit?
the holiday pay will be beased on your reduced salary.
Salary sacrifice is actually a reduction of contractual salary not a deduction from pay (even though it's often shown as a deduction on payslip).
So your holiday pay (along with any maternity pay) should be based on reduced salary.
for example if your salary is £28,900 a year and you get £200 a month Childcare vouchers through salary sacrifice salary, your annual salary is reduced by £2400 so it is now £26,500.
This means that your weekly pay (based on 53 week tax year) is £500 a week, so holiday pay would be based on that rather than £545 which would be your weekly pay based on your original salary of £28,900.