I've just recently battled my daughter's school in terms to her special needs support. I'm lucky that my brother is a lawyer and stepped in on our behalf.
Here, there is no such thing as 1:1. She shares EA support with another child in class, and the EA has up to 5 other children when they are outside, which is unacceptable to me.
In trying to let go of full control, I tried to take my daughter's needs into account. My main concern is she is a flight risk, so as long as whomever is watching her and in charge of her care understands that and keeps an eye on her then I'm okay.
She will test and push boundaries, but then so do most children. However, if she had a more serious need (aside from her being a flight risk) as in chocking, seizures, uncrontrollable stimming, etc... then I would be livid and asking why.
You know your kiddo best.
If you feel uncomfortable, then definitely speak up! I'm not sure about across the pond, but here everything is in writing. So if they were to ever leave her with someone who isn't trained as an EA (etc) then they'd have to notify me. If I wasn't comfortable, I could contest it.
Massive hugs, school is a scary thing to begin with... even more so when you don't trust the people who are caring for your child.