The Mobile First Aid Unit -- Trained in Peacetime the Mobile First Aid Unit is Ready for any emergency. The Mobile First Aid Unit is staffed by National Hospital Service Reserve nursing auxiliaries. In this typical unit the doctor's car is on the left and there is another car and a van to take the rest of the team and their equipment. The Despatch Rider (centre) will reconnoitre the route to the site of the incident and direct the rest of the unit there. May 12, 1952. (Photo by Central Office Of Information Photograph).