alt Hacker NewsI don't think I would describe the NMC as "just up the road". It's the same physical site.
If you consider the NMC "just up the road" then the Bletchley Park site you're thinking of is also "jump up the road" from er, Bletchley Park, a stately home that's less interesting to a nerd than either the NMC or Bletchley Park museum about war era "intelligence" but might be fascinating if period furniture is more interesting to you than the world's first (for many different values of first, the museum has several options, but not all of them) programmable computer.
the nmc is most interesting, but also pretty cool to see turing's office in hut 8 (i guess the portable classroom like structure for a computer lab is a trope that goes all the way back to the beginning)!