Hi, Red Dog,
good map of Drvar region you can find on http://www.mojdrvar.tk under link "Polozaj".
The only true about battle is from german sorces. And, Tito wasn't there. My grandfather drive him and Churchills son to the airport 2 days before the battle.
It is quite intersting that only 2 british survived and one of them was Churchills son Randolph
Sorry for bad english