welcome Emu. glad you have not experienced anything major and are enjoying new ride.
I also have a gls at present, and although currently off rd, previous fuel consumption was low because of low mileage. However, engine to car size ratio is out of balance causing high fuel consumption the higher the mileage done.
but if economical driving is used you may find fuel use will not be so high.
Enjoy your ownership and many happy mileage.