The following information is available on the ICO web site. Accessing pupils' information | ICO (I have highlighted an important section in bold).
Firstly, anyone with parental authority can request access to a child’s education record under education regulations. This would cover information such as; the records of the pupil’s academic achievements as well as correspondence from teachers, local education authority employees and educational psychologists engaged by the school’s governing body. It may also include information from the child and from you, as a parent, carer or guardian.
In England, schools are regulated by The Education (Pupil Information) (England) Regulations 2005. Those with parental authority can apply to the school to view an education record or receive a copy. Importantly, this right only applies to all local authority schools, and all special schools, including those which are not maintained by a local authority. Independent schools, academies and free schools are not obliged to respond to a request for access to a pupil’s education record under this legislation.
In addition, independent schools, academies and free schools are not obliged to respond to a request for access to a pupil’s education record, although they can choose to do so.
You may also want to consider a Subject Access Request. A general Subject Access Request is wider in scope and would include all data that is processed by the school. This would include all details on the educational record as well as other correspondence. Technically, a SAR can be submitted by any person with parental responsibility but unfortunately it is not as simple as you may think. The best interests of the child should always be considered but the overriding principle is that, even if a child is young, their information still belongs to them, and it is the child who has the right to access their information.
On receipt of a SAR from a parent, the school must therefore consider whether the child is mature enough to understand their right to see their personal information. If they believe that the child is mature enough, they can reject a request from a parent and only respond if the child submits a SAR themselves. Guidelines suggest that a 12 year old is generally considered to be able to make a request themselves.
The school may also try to rely on the exemption that organisations have in that they do not need to provide the data if they believe that complying with the request would be likely to cause serious harm to the physical or mental health of any individual. It may be worth trying to counter any attempt to reject the request on that basis by explaining why the provision of the information will not have an impact on her mental health.
I hope that helps.