Panic over ,people. Was messing around today and I think that all I need to do is have it zoomed in on the display slightly more than I had been. It seems that if it is about five clicks out from fully zoomed in then even when you hit 60 the minor roads stay on screen.
Otherwise I am pretty impressed with it. The feature to choose between Shortest distance/quickest time/ offroad is a lot handier to use than the 550 and far easier to pick which route to go by.
Thanks for the replies.