I remember Donald Blackwell well. In those days there was still a lot of respect for one's elders and he was like the Headmaster, with whom one mainly associated on serious business, although he was a perfect gentleman and bore a kind heart.
Donald brought his technical henchman David Petford with him from Cambridge and they always worked together; David had his own henchman Peter Ibbotson for many years.
Donald's laboratory, comprising the solar furnace and spectrograph, was a wonder to behold, tucked as it was in a basement of the Observatory. The power for the furnace came through a huge transformer orientated so that, if there were ever a short circuit, the core would jump downwards rather than demolishing its surroundings. The spectrograph was in a long subterranean tunnel whose air had to be left undisturbed for a couple of weeks before measurements could begin.
Donald was never one to do things by halves: his Cambridge PhD thesis ran to two whole volumes, for instance. His beautiful precision work was reflected in his minuscule handwriting and he also ran the affairs of the Department punctiliously, polishing the reports and balancing the books to perfection.
During most of my time in the Department, the experimentalists and observers tended to occupy the main Observatory building and there was a large wooden hut housing the theoreticians, led by Dennis Sciama. A visiting American lady once exclaimed "Gee, so Dennis isn't the Prof.?" which ruffled a few feathers at the time.
The Royal Astronomical Society held monthly meetings in London, which many of us attended, and Donald would often ask challenging questions of the speakers, along with Donald Lynden-Bell and others of that rank. I am not sure that things are held to quite the same standard nowadays.