For a 2015 F-Type R. Looked through the menus and couldn't find it.

 

There is no estimated MPG; however, you can get a calculated MPG aligned with your trip odometer. It shows up in place of the odometer reading.
If you haven't tried it, press the button in the middle of the left stalk and it will cycle the odometer display through total miles, est distance to empty, trip odometer, average speed, and average MPG.

The last three all reset together if you press and hold the button, so they're only a "trip" view.

 

Ah, okay, thank you very much, and I do understand that it's only an estimate, and typically optimistic, but am still curious.

 

We’ve generally found the trip computer to be around 2mpg optimistic. Note you can select the trip computer bank in the menu. ‘Auto’ means everything (including fuel economy) resets each time you shut off the car. I use bank A, as my fuel gauge no longer operates.