Depending on where you are this may be problematic even if there is a valid history in DDs medical notes. See below:
"Dear Head Teacher or College Principal
Medical Certificates for Students absent from School or College
I write on behalf of X, the statutory representative body for all general practitioners in the county.
Dr???????? has recently been approached to provide a medical certificate for ????????.
In respect of his/her absence from school or college
NHS GPs provide medical services and have no professional involvement in education or school attendance monitoring. In general, family doctors do not provide sickness absence certificates for children as the parent?s explanation for the absence is should normally allow the school to ensure any health related concerns are addressed.
Furthermore, GPs do not normally provide short term sickness certification for periods of less than 7 days and they are unable to issue medical certificates for longer periods of sickness absence unless the patient was seen by the GP at the time of the illness. Please note that NHS medical certificates are provided only for employment and statutory sick pay reasons. They may not be issued for any other purpose.
If a certificate is required by you for education purposes, this constitutes a private service and the GP practice may levy a charge. The person or organisation that requests the certificate will be billed accordingly. Obviously any such request must be accompanied by the written consent of the parent or legal guardian if the student is under 16 and the student?s own consent if he or she is over this age.
Provision of medical certificates for school children is not part of a GP?s responsibility and a refusal to provide this certification is in accord with the Government policy to reduce GP paperwork and preserve valuable GP time for clinical care. Please see; www.dh.gov.uk/en/Publicationsandstatistics/Publications/PublicationsPolicyAndGuidance/DH_4003147
When a child has missed an exam the examination boards do not require the GP to provide a certificate before special consideration of the case. Please see www.jcq.org.uk/attachments/published/428/Final%20%20RAG%2007-08.pdf
There is no statutory obligation on NHS providers to produce certificates covering absences due to illness for students claiming Education Maintenance Allowance.
In cases where recurrent short term illnesses or a more prolonged spell of illness is causing concern it may be helpful for an Education Social Worker to speak to the GP, again after proper consent has been obtained.
You will understand that it is most important that the GP retains the full confidence of any child, but it is particularly important for those children that have problems resulting in poor school attendance where a trusted doctor-patient relationship may be critical for the young person?s future care.
I hope you will understand therefore that it was not possible for the GP to issue a medical certificate as requested on this occasion."
It is not impossible - in the end my GP just signed one of the sickness certification pro forma. It took about 20 minutes which was mostly him staring at DS (in a world of his own at the time - DS not GP) and reading DS's notes.
Keep it practical - school want sick note to record absence as authorised - without a sick note they are pressuring DD to attend and this is having a counter-productive effect and increasing anxiety.
Good luck. 