What's going on here then?
Go to the listed coords and eventually the penny will drop!
Some devices may struggle with reaching GZ inside Grand Central.
To aid locating what you need to find, it is 72 paces from the Bull ring entrance & 52 paces from the bottom of the escalator.
ABCDEFG
N52° 2 (B+F) . C (F+G) (F+B)
W001° 5 (A+D) . (C+E) (B-C) G