Worst: about 19-21 mpg (urban).
Overall: 23.8 mpg (~3,300 miles, about 2/3 urban).
Best: 33-35 mpg (after decent runs).
My typical cruising is around 60mph as long as road and traffic conditions allow, but I'm quite happy at 50mph. I'm in no hurry and the enormous roof rack makes quite a bit of noise at speed. Before I got the rack I would do 70(ish)
mph quite happily and it still easily gave 30+ mpg.
240 DL estate with huge roof rack, 2.3 litre, Cisac carb, 5-speed, tall diff.