The additional funding is means tested but the testing basis is quite wide and I would imagine a lot of people will fall into the category.
From the GOV website:
The additional 15 hours of free childcare is available for families where both parents are working (or the sole parent is working in a lone-parent family), and each parent earns the equivalent of 16 hours a week at the national minimum or living wage, and earns less than £100,000 a year.
I fully support childcare settings saying no - and I will benefit hugely from the 30 hours as I have a 21 month old and another on the way! If they are forced to do it, they are not getting in enough to make it worth their while. Most nursery's, preschools, child minders are businesses or charities, they need to cover at the very least costs and on the whole make a bit of a profit - it is how the world works.
As always the government don't seem to get the idea that somethings do cost what people charge also don't seem to have left and right hand working together - nursery staff wages will have just gone up to the Living Wage, so that cost has increased, but they also want to then double the reduction in fees they can get by only giving less than 4 pounds an hour for funding.
It doesn't add up.