Canberra cockpits
The other big difference between the PR9/SC9 and the rest of the fleet was that the 9s had no transport joint being built by Shorts.
The transport joint was a means of fastening a fuselage, just about any one , to a cockpit, again various as in the RAE miscellany. It may be seen on some photographs as a slightly tilted vertical line behind the cockpit
The 9s were a direct build and so no tranport joint was made and this meant exchanges was impossible. When the cockpit fatigue life was used up the aircraft was scrap