I have just stumbled across this site and can't find it referenced elsewhere on the Forum.
http://www.forsythe.demon.co.uk/other_pages/mark1nums.htm (http://www.forsythe.demon.co.uk/other_pages/mark1nums.htm)
Mods my apologises if it is "hiding"somewhere on the Forum and /or I have posted this in the wrong place.
You may find it helpful for (amongst other things) matching running numbers and manufactures model numbers or identifying coach types from the running numbers.
To quote the author it's a "study of the Mark One British Railways Coach in model form. A more or less completed manuscript for this covering ready to run models in 00/TT as well as Kitmaster kits exists. Additional notes covers kits and other gauges and Marks. "
Ray