If you miss it because you're now in the UK, there's a museum with an impressive collection (especially of the very first machines; EDSAC, WITCH, and Colossus) just outside of London.
I took a bunch of photos when I visited [1], I could've easily spent days there. It's unlike any museum I've been to before, towards the "end" there are lots of rooms with just piles of books and computers you can sit down with for however long you wanted - lots of tactile interaction! It was also wonderful to see machines like Colossus running as well as all manner of oddities like early UNIX systems, air traffic computers and calculators.
I frequently go to London, and it's definitely worth popping to MK for a day just for this!!