Hi again Donna,
I think I have sorted it. Before the 3D mod there were scales underneath the green traces on the ppi radar. I now realise that these have been replaced by the numerical dials to the left. Incase you haven't seen it here is a link to a training page by John Channing about using 3d radar.
Thanks for all your help,Bruce
http://www.subsim.com/radioroom/showthread.php?t=172535