Fuel Consumption

[onestar]

Hi all, before 40K miles I could drive between London and Glasgow about 460miles on one tank of petrol and still have about a 1/4 tank left. At 40K miles fuel consumption seemed to drop, and the oil consumption went up. The engine was replaced and the oil consumption was fixed. But the fuel economy seems to remain bad. Drove London to Glasgow and had only 5 litres left (filled up 55litres on arrival).

Whats gone wrong? I've tried supermarket fuel, BP normal and special, Shell normal and vpower. But mileage is still relatively bad.

The mpg reading has always shown 35mpg or around there. But I used to go easy London/Glasgow with fuel to spare.

Any ideas?

Thanks