Hi Damian,

It's difficult to assess why this may be from afar, but we can give you some general advice that might help before you go to a garage to have it plugged into a diagnostic computer to see if there are other problems.

1 - Check your tyre pressures. Low pressure will lead to worse fuel consumption.

2 - Make sure you're not carrying extra weight in the boot, such as a set of golf clubs, as this worsens the fuel consumption.

3 - Likewise, if there's a roof box, bike carrier or roof rails fitted and not being used, remove them, as they cause extra drag, worsening the fuel consumption.

4 - Make sure you're not leaving the rear window demister on permanently as it uses a lot of energy.

After that, I'd suspect it's something like a dirty air filter or a sticking brake causing the issue, but you will need to bring the car to a good mechanic to have it looked at.