Is V's lair based in a real place?

Question

When Evey wakes up in V's home, he tells her she has to stay with him because otherwise she could give away the location of his lair. She counters that she has no idea where they are, and he says the following:

You know it's underground. You know the color of the stone. That would be enough for a clever man.

This has always bothered me because it seems to be so insanely untrue. Those two facts couldn't possibly be enough to locate something. Could they?

Answer 1

V's secret hideout is an abandoned Victoria Station.

This is confirmed in the film canon by the shooting script (referring to the location as "Interior : Victoria Station") as well as the quote;

V : This is the old Victoria line but it is blocked, blocked somewhere between Whitehall and St. James.

and

Suddenly, Finch stops. Carefully, as if reaching to touch a butterfly, he slips a single sheet out from the sheaves covering his desk. The paper has a long list: the names of all the Queens of England. He has circled in red the V in Victoria. When it hits him, it hits him like a falling safe.

FINCH : Christ! That's it! It's got to be it!

and

The shadow is cast by a sign for Victoria Station, part of the abandoned subway.

And the film's official novelisation

And only two London tube stations started with V: Victoria and Vauxhall, and the latter was south of the river, away from the centers of power... away from all the scenes of Vs exploits. If it was anywhere, it had to be Victoria...

Not far away, the target of Finch's search was dancing slowly with a beautiful woman in his arms.

Within the Alan Moore/David Lloyd comic-books we also see that the final scene is indeed set inside an abandoned Victoria Station.