Self certification
By law, you do not need a doctor’s note if you are off sick for up to seven days. Fill in this form called SC2.
Your employer should not request a sick note from the doctor during this time. If you want a sick note during this time there will be a private charge for this.
If your employer has reason to inquire about a spell of sickness, they are advised to write to the doctor, including written permission from the you, and a report may be issued. A charge will be made for such a report.
Fit notes
After the first seven days you will require a medical certificate or “Fit Note”.
If you have not already had a consultation with the doctor about this episode of illness, or if we have not received relevant documentation such as a hospital letter, you may be asked to book an appointment. If you have not consulted with a doctor for a while about this problem, or if it is your third note, we may also ask you to book an appointment.
If you do not need to see a doctor, a fit note can be requested here:
Return to work
You do not need a certificate to declare fitness to return to work.
See here for details: https://www.nhs.uk/common-health-questions/caring-carers-and-long-term-conditions/can-i-go-back-to-work-before-the-end-date-on-my-fit-note/