GP practices do not provide sick notes for school children or those in education. Parents/guardians are responsible for excusing their children from school and this should be evidence enough.
The Fit Note, or to give its official title, ‘A Statement of Fitness for Work’ is used as a form of evidence that can enable either proof of illness to an employer or used as proof to access health-related benefits. It can also be used as evidence for eligibility for statutory sick pay (SSP). It is designed specifically for those in work and not those in school.
As such the surgery is not able to supply a MED3 for a child’s absence. Often the only proof that should be required for a child being off sick is a note from the parent/guardian/carers. If a child is off with a long-term condition, they will be under a specialist and they will be responsible for providing an assessment if requested.
If you are a student and a letter is requested as evidence by your college or university of your absence, this is a private, non-NHS service and as such will attract a charge.