There's a lift between the lower and upper concourses.
The lift is on the left-hand side of the concourse as you come in via the main entrance. The call button (up only) is to your left of the door. Note that the button about a metre to your right of the door is the assistance button.
The lift is between the ticket sales windows and the stairs on the north side of the concourse. The call button, (down only) is to your left of the door.
There are clear, spoken announcements.
The controls are on the right-hand side as you go in, from the top:
FENCHURCH STREET STATION
© 2009, Terry Robinson