Depends on how I drive, had the car 10 months and keep a close eye on MPG all the time.
Lead foot mode:
Town (start stop traffic) - 36mpg
A-roads bit of start stop at junctions and roundabouts - 40mpg
motorway (50 miles of non stop motorway) - 38mpg
Normal mode:
Town - 40mpg
A-Roads - 42mpg
Motorway - 42mpg
Eco Green boring mode:
Town - 42mpg
A-Roads - 45mpg
Motorway - 48mpg
This is all measured off the trip computer so isn't super accurate but that's what I've seen over the last 10 months.
To be honest, driving all eco doesn't get much more than just driving normally but it requires more thought and makes for a much more boring drive so I usually don't bother unless its a long motorway journey.