Bob S, I'm on a fishing trip as I don't know the answers. I would have expected the ARP to have a "W" on their helmets, but there was some local improvisations before national standardisation. They could be local volunteer ambulance drivers. So, any help in identification is welcome. I don't think that paint was rationed, but it was in short supply, as were paintbrushes, and for domestic use limited to a three-colour ultilty range: cream, green, and brown.