You only need a doctor’s note if you are unable to work and are ill for longer than seven calendar days. Your employer will provide you with an SC2 self-certificate form for shorter periods of illness. If you are off work longer than seven days and require a sick certificate, the doctor must either see you or have a written report from another doctor who has seen you for the relevant illness (eg. hospital discharge letter) before he can issue a certificate. Requests for continuing sick certificates should be made in writing to reception, unless the doctor has asked to see you.
Remember – a sick certificate from your doctor is not needed for the first seven days absence. BY LAW, employers must accept an SC2 self-certificate covering this period. If your employer still insists on a certificate covering the first week’s absence, then, as this is not an NHS service, a private certificate will be issued on payment of a fee, currently £15. Information for employers on sick certificates is available here