Re: History of Science Museum...
Happy to say that the giant moon pastel (where you said it is), the early scientific instruments (top floor) and the copy of Dee's table (entrance hall) are all still there. Although I focused on the medical exhibits for this article, the History of Science Museum has treasures from a range of sciences. Another is a blackboard that Einstein used when he lectured in Oxford, up on the wall to the left of the bed pan/biscuit tin cabinet in the basement (https://hsm.ox.ac.uk/blackboard-used-by-albert-einstein). Just possibly this is more significant that the Sinclair calculator I mentioned.