I rode timidly for a tank, kept rev's <5k, for my normal 30/40/50mph commute, just made sure I pulled away smoothly using all the gears and carried momentum as much as possible ... over a week I averaged about 71.5mpg according to the dash, at ~220 miles I filled up when the last block started flashing, it took in about 15 litres, so had about 70 miles left to go before it ran dry...
As soon as I had filled up I rode like a hooligan and averaged ~50mpg for the next 100 miles.