Re Lister Noble's "Big Picture," with my instructor it was "The Concrete Radial," ie the motorway. Sensible advice. Unless you have been lost for a very long time without noticing anything, you will not be far from where you ought to be so any prominent geographical feature will give you a clue. Otherwise I'm in the tell somebody camp. It's better to call up, either the unit you have been working or D&D, and put them in the picture. Thereafter any one who criticises you is an a*^%$@le.