Nick Cooper writes:
In that case, technically it was part of the LU infrastructure - and
is now - but it wasn't part of the operating network at the time. I
take it that was why you were being vague on that point?!

That's what made me *think* of being vague, but the reason I decided
to *be* vague was that I thought it made it a better puzzle that way.
If I'd thought about the case of Moorgate, I would have adjusted the
wording to include places that were formerly part of the Underground,
or something like that.
--
Mark Brader, Toronto "It's the almost correct solutions that
are the most dangerous..." -- Dave Eisen