Please note that sick notes are issued at the Doctor’s discretion and only after he/she has seen and/or examined you. The doctor has to sign a legal document to certify that in his/her opinion you are unable to attend for your normal work.
Sometimes a repeat certificate may be issued if the doctor knows you well and is persuaded that your condition may take longer to improve. However he/she may still need to see or speak with you before extending a sick note.
GPs do not issue sick notes for the first 7 days of absence, which can be covered by self-certification. If your employer requires a sick note for the first 7 days then this can only be issued as a private certificate for which there will be a charge.