Check the childcare interactions

Working families can get either Tax-Free Childcare (up to £2000 per child, age 0–11) or Universal Credit Childcare (up to 85% of costs, age 0–16), alongside free childcare hours.
Universal, targeted, and extended childcare entitlements cannot be combined—families can only use one type at a time.

https://www.childcarechoices.gov.uk/combining-schemes