It does say that, but news organisations are notoriously poor at articulating the constitutional situation in the UK.
In this case, for example, the move has no effect on Scotland - the education system there is totally devolved, and AFAIK there's no concept of the "free school" or academy model which has been introduced in England and Wales. I'm not sure about the situation in Northern Ireland.
The Scottish Secular Society has been campaigning for a similar ban in Scotland - this will probably happen at some point, although my experience suggests that there's not as much of a problem there anyway.