As a result of the assistance I have obtained on this thread mainly from Paul and also from Naz, I am now using Level II in a basic but useful mode.
I use the main Level II screen plus the Island and Arcipelago screens mainly to tell me whether I should enter a trade ( or not ), looking to see if I can get out at or near my planned stop, and also in conjunction with the Time and Sales screen as a kind of momentum indicator.
Thanks for your help guys.
I am up and running and making use of this valuable tool now.