"This is London":
It was filmed in three disused stations - Down Street near Green Park,
Strand and Aldwych.

One suspects that this means "two disused stations". There have been
two stations called Strand, but only one of them is now closed, and
it's the same station later known as Aldwych. (The other, of course,
is now the Northern Line part of Charing Cross station.)
--
Mark Brader | "Oh, especially if it's accurate. There's nothing worse
Toronto | than *accurate*, ill-informed, irresponsible press
| speculation." -- Lynn & Jay: "Yes, Prime Minister"