An interesting document I had not come across before. This "Orders To Parties" form from the Lambeth Civil Defence area in London covers a lot of information about an incident.
I've tried to decipher the abbreviations but one or two are not obvious:
SP - Stretcher Party (term used in London for First Aid Party)
CDP - not sure on this one - something Party
AMB - Ambulance
REP - Repair Squads (gas, water, electricity, sewage, telephone etc)
MU - Mobile Unit
R - Rescue
MC - ?
DCP - Decontamination Party
News about interesting insignia, ARP related info and period photos that turn up.