Yes, parents have a right for their child to just access funded hours only without incurring any additional charges, but funded hours may only be supplied for certain hours and days of the week which are determined by the provider - but ask your childcare provider for details. Parents are under no obligation to access non-funded hours, consumables or services just to access funded hours.
Settings must also not charge a 'top up' which is the difference between the rate they charge and the rate they are paid.