As promised (a little while ago) I have scanned the entirety of "The Durham Plan" - Durham's first comprehensive plan, from 1927. It's a fascinating read if you are into figuring out what kind of thinking guided the course of what Durham became over the middle 1/3 of the 20th century. (And if you are reading this website, you probably are.)
It is a big pdf file (84 MB), so caveat emptor - I'd suggest you right-click (option-click for Mac folk) on the link below and select "Save target as.." or similar.
Download the plan here.