Civil Defence ACC (Ambulance Casualty Clearance?) Leader Helmet

A selection of civil defence helmets, some with quite rare and scare markings, has cropped up on auction website saleroom.com. The below is a white party leader helmet with "A" over "CC" and double chevron. The auction house has this listed as meaning "Ambulance Casualty Clearance" though there is no documentary evidence to currently back this up this assertion. The use of rank chevrons was seen on a number of post-war Civil Defence Corps helmets and there is a possibility that the helmet may date to this period (1949 onwards). If you know more, please drop me a line.

WW2 Civil Defence ACC (Ambulance Casualty Clearance) Leader Helmet *front)

WW2 Civil Defence ACC (Ambulance Casualty Clearance) Leader Helmet (side)

WW2 Civil Defence ACC (Ambulance Casualty Clearance) Leader Helmet (rear)