I visited the London Metropolitan Archives today and took a copy of "Air Raid Precautions Memorandum No. 17 - Civil Defence Uniforms". This 44 page booklet is a veritable mine of information about the pattern numbers, all the various uniforms including footwear as well as some photographs showing the correct location for where badges should be applied. It is an excellent resource. If you would like a digital copy for a small fee of £2 please contact me.
News about interesting insignia, ARP related info and period photos that turn up.