Emma, it is not near Xray as far as I remember. The ultrasound you want is in the maternity day clinic bit. As said in main rotary door thing (if you can fit your bump in it
) and turn right, left at shop then right just past the lifts. That is the long corridor and as you walk down you will see the walls change - that is the old hospital. What you want is farther down on the left.
It is well signed though.
As you turn off the corridor the first room and desk is for up downstairs problems - walk straight on through the door into the big room that looks like a Japanese fishing boat
and the desk is on the left.