Make sure that however you decide to carry out risk assessments the process is clear and built in to the Health and Safety policy. For standalone and independent / private nurseries/ pre-schools the highest authority for policy will probably be the Manager in conjunction with a management board or board of governors, who together represent the concept of 'employer'. In most LEA establishments the local authority can be held to be the employer, but the head teacher and governors are still responsible for implementing the policy on site as it were.