This is a bit second-hand but I had a teacher in secondary school who had been a navigator on Javelins and Vulcans and I remember him telling me that they assumed that the landing sites for their planned war missions would not be there if they ever arrived at them.
Sobering stuff even for a 15 year old space cadet in 1980!
PS his name was Mr Siviter if he or anyone out there who remembers him is reading this. I think I've still got somewhere the navigation / bombing protractors he gave me.