They could ask for an early review, but if the school remains the parents’ preference the LA must name that school unless the LA can prove:
-The setting is unsuitable for the age, ability, aptitude or special educational needs (“SEN”) of the child or young person; or
-The attendance of the child or young person would be incompatible with the provision of efficient education for others; or
-The attendance of the child or young person would be incompatible with the efficient use of resources.
The bar is high, far higher than many realise, and requiring 1:1 in a MS wouldn’t meet the threshold. And, unless the school is wholly independent, if the LA can’t prove one of the above they can and must name the school regardless of if the school object and claim they can’t meet needs.
That’s not to mention, even if they did call an early review and the 1:1 was removed or the pupil moved setting the provision must still be provided until the amended EHCP is finalised.
And most local authorities deliberately write ehcp in such a vague way that what needs to be provided isn’t clear. Things like “high level of support” could mean anything!
Which is why I said “if it’s in the EHCP”. Vague and woolly EHCPs is a completely separate point. If the 1:1 is specified and quantified in the EHCP it must be provided, and if it isn’t it can be enforced.