Chris - I know you well and I am ashamed of your suggestion that we were inexperienced pilot/navs with rookie copilots in the right hand seat.
I was a non - Hamble (Oxford) bright young thing.
I, and the others, held a full nav licence and you must know that the CAA didn't give them out easily.
There was considerable under supervision training (about six months in all parts of the world) and the exams were the ATPL exams with a couple of additional nav papers.
Most of the instructors were ex-straight navs.
What I do remember is the satisfaction at "being in command" of the navigation at the age of 24, the other guys would go anywhere you told them..
As for doppler over the desert, I don't recall it being a problem on the VC10 - maybe we were better than your straight navs!!
Africa was relatively easy, generally light upper winds, not much change in magnetic variation and a mercator chart
The most difficult sectors I found were the lhr to Caribbean in daylight - no loran, no consol (ahh consol!!), just sun (moon and venus if you were really lucky) for parts of the route.
The chart was a Lambert and grivation played an important part.
I think my best moment was a mer passage between Fiji and Honolulu - we were delayed as this sector was usually a night sector.
Best seat on the flight deck as you had a proper table to eat at (only reintroduced with the A320).
I'll stop waxing lyrical and await your apology!!
Alan