I have uploaded this pdf onto my server. I eventually managed to download a copy. I understand that the copyright has expired so it is now in the public domain. Most sites I visited wanted a membership fee or something before you could download the file. As I have my own server I thought I would give something back to the group. click on the link below and help yourself.
The file size is 33.7MB
http://smiddleton.net/images/models/spitfire/CamouflageandMarkings1-SupermarineSpitfire.pdf
Happy modelling
P.S. PM if you have a problem