The navigator is worth more than a Jubilee for sure. Unfortunately the jubilee gained a bad rep for seizures blamed on an underdeveloped motor but it was actually caused by the points cam causing the timing to slip and the engine grenading. The issue was solved by the factory fitting updated points cams but by then the damage was done and the jubilee was doomed. The jubilee was also built to a price and used Francis Barnett and James frames, forks and wheels. I think the Navigator used the heavyweight Norton running gear including road holder forks. Shame it's not the Electra, they are selling for good money due to having the electric starter (when it works) and the old guys who insist if having Brit bikes can start them.
You could send some photos to Andy Tierman, he will give you an idea of value but remember he's a dealer.