The NHS Guidance has now changed.
Accessing children’s records
A person with parental responsibility will usually be entitled to access the records of a child who is aged 11 or younger.
Children aged 12 or older are usually considered to have the capacity to give or refuse consent to parents requesting access to their health records, unless there is a reason to suggest otherwise.
Although British Medical Association guidance says that every reasonable effort must be made to encourage the child to involve parents or guardians.
https://www.nhs.uk/common-health-questions/nhs-services-and-treatments/can-i-access-someone-elses-medical-records-health-records/
What happens next:
We are contacting all mobile numbers on our records of 12-16 year old patients via text with a consent form for the child to sign and return.
We have had to delete all mobile numbers we hold at present to ensure we only have the number the child provides and consents to.