Hi Fris B. Fairing, they were good days - lots of innovation and lots of overtime. In relation to NSR I seem to recall once modified it would have been an expensive proposition to be mod back to an airstair door - unless they were able to buy a whole cargo door and replace the lot, so I don't know what was done for that aircraft.
Probably warrants another thread, but Hawkers used to make the door completely. We made formers and went to the rubber press at De Havillands and pressed out O condition 2024 which was then heat treated by them. Once heat treated they were bought back to 275 and put in a jig for assembly of the door. A lot of the latching mechanism was taken off the airstair door and reused on the inward opening door. The door was on articulated arms attached to modified yacht sail roller carriage thingies and tracks mounted on the floor. The door was pulled inwards and rolled forwards into the fuselage. I remember going on the test flights and once strapped in opening the door and making sure it could be closed - there was a deflector on the forward edge of the opening. Have some photos somewhere, after modification the hull was ground pressurized to 1.5 times max diff to check integrity.
Along with the bubble windows some of the aircraft were modified with camera hatches, seem to recall one aircraft had two camera holes. There were also two tubes in the luggage area for deploying (i think) flares in flight, the flares were put in on the ground and released without having to depressurise.
Thanks for the info on where they are now. I wonder if NTG is one of the modified ones.