I manged to purchase a job lot of Civil Defence insignia on eBay and among the various items were two pairs of shoulder titles for a Fire Guard Sector Captain. I have previously seen the printed version of this rank but had not managed to get hold of the embroidered ones until now. The Sector Captain was the lowest uniformed rank within the Fire Guard service and wore a helmet with two half-inch black bands on it. In all photographs I have seen it has always been a Mk II helmet rather than a Zuckerman.
News about interesting insignia, ARP related info and period photos that turn up.