On 7 Feb, 11:36, Roland Perry wrote:
There's a lift to a mid level by the metropolitan line stairs (the set
leading from the tube ticket hall)
Yes, but the level it goes to is not deep enough to be called a
"sub-basement. If there was a sub-basement, that lift could be extended
(downwards), assuming the sub-basement extended to whole width of the
gatelines (and the lifts down to the Northern Line are at the opposite
end).
"Sub basement" in the sense of being below (ie. "sub") the basement
level (ie. the ticket office level).

http://www.perry.co.uk/images/kx-composite-b.jpg
So where the red-circle is.
No. Diagonally southeast of there. At the corner of the ticket hall
Can you give an X/Y grid reference (where the red dot is 3.4 across and
4.2 up)?
http://www.perry.co.uk/images/kx-composite-c.jpg
5 along by 3 up.