If you're visiting London, head north on the train for about 30 minutes and visit the museums at Bletchley: Bletchley Park itself, which documents the British WW2 codebreaking effort, and is amazing, and next door to it the National Museum of Computing, which has samples of basically every computer ever made, most of which you can play with, and which is amazing. (They have a working decatron decimal-based computer! Which you can play with! <a href="https://goo.gl/photos/FiTQAM8VkPknCAJR7" rel="nofollow">https://goo.gl/photos/FiTQAM8VkPknCAJR7</a>)<p>But they <i>also</i> have a BBC Micro lab, complete with a Domesday Disc setup. Which you can play with. It's surprisingly usable.