Group portraits of Civil Defence volunteers are always interesting for throwing up details. This one has a Fire Watcher - FW - helmet tucked under the legs of the man at the front. A peculiarity on this photo is that it appears that the ranking members are only wearing chevrons on their right sleeves. Also, everyone is wearing a beret and it's not often that you see ladies wearing them.
News about interesting insignia, ARP related info and period photos that turn up.