Does the incident need to be witnessed?
No, your incident does not need to be witnessed, although if there are witnesses around then it always helps to obtain their details for future use. If there are no witnesses, if at all possible take pictures of the incident site, what caused the incident (car, pothole, spillage etc) and also of any injury you have sustained. It may also assist to identify any nearby shops or buildings that have CCTV which could have recorded the incident or to report the incident to member of staff if the incident occurs in a shop.
Should you seek medical attention after the incident, make sure you explain clearly to the Medical Practitioner what happened and how you were injured. Whilst seeking medical treatment is not a requirement, we do recommend that if in doubt you get yourself checked out. Ultimately, the incident did occur and you are of course still entitled to make a claim if you were not seen by anyone.