Have you tried the NHS health guide at https://www.nhs.uk/conditions/.
Or if its to do with a soft tissue injury, head lice, teething, toothache, or backpain etc? Have you tried your local Community Pharamacist. One of the services that community pharmacists are trained to provide is the treatment of minor ailments.
Or if you need a sick note or referral then you can complete one of the forms found here https://www.online-consult.co.uk/org/barton-house-group-practice