Did Leeds and back on my own - 430 miles to the tank
Did Liverpool and back with a full car and overnight luggage, and although we didnt hang around, got 420 miles to the tank
For work journeys - 60 mile round trip of Dual/Motorway/A road and B road (real mix!), I get 380 to the tank.
Worst I have had is 340 (last fillup)