I usually get between 32-34mpg and my last few tanks i've been getting around 30mpg. I've been doing the exact same driving and have no warning lights etc.

 

The car has a full service history and under 20k miles at 4 years old so not sure what it could be?

Hi,

 

Check if you have been using air con, or running with the windows opened or even the tyre pressure..... - even if you drive at a prox the same tolerances those can affect it.

Windy? Makes quite a big difference.

 

Check oil. My mpg used to dip when the oil was getting low.

 

Drive a short distance and check all 4 wheels and brakes for heat. Might be a sticky calliper.