More than 29 mpg is achievable depending on driving conditions. If you're flooring it all the time then I wouldn't expect to get much more than the mid - 20's. However there are techniques you can use to improve fuel economy.
Increasing the tyre psi's to 38 all round will help, especially if you drive in ECO mode.
Driving downhill or coasting (in gear !) towards, say a town with a30 mph sign you can come off the throttle completely for 100 yards or more before the speed limit sign, the car will maintain speed by itself, slowing gently to 30 mphwithout using any fuel. This avoids braking but may take practise.
If you can, try smoother driving so anticipate more by looking farther ahead, this will help economy as you will be changing gears less and reducing the frequency of harsh braking / acceleration.