Curious Single Chevron On District Warden Battledress

A nice group shot of warden's towards the end of the war (going by the number of war service chevrons on show). The group is from Post 2A in Fetcham, Surrey. This chap in the centre, bottom row appears to have some insignia at the top of each sleeve - possibly Home Guard shoulder titles and also three bars - which is normally for a District Warden. He also has a peculiar single chevron on each sleeve - the chevron appears to have a distinct outline in a different colour. This single chevron on a senior rank battledress is new to me.

The chap at the back, second from left, appears to be wearing a couple of British Red Cross First Aid Proficiency medals, worn oddly, on his right pocket for some reason. 

Also, a few berets don't have an ARP badge - not often seen. As the chap bottom right has no war service chevrons on his right sleeve he could have joined after '43 so didn't get issued one.

The group also wear the leather anklets - not often seen worn.

Wardens from Post 2A in Fetcham, Surrey.

Close up of the single chevron worn by a District Warden.