My 20 mile commute to work is along back country roads and through small villages, ideal for the Hybrid. Some fairly long stretches of 30-40 mph that allows me to coast along in EV.
Currently my record high is 62mpg and I constantly get between 50-55mpg (bear in mind I drive the F-Sport).
However, on one drive home late at night, I managed my lowest at 24mpg. That took some doing, as if you get stuck behind a slower driver, the economy rockets up! :)
On long motorway journeys at 70-75mph I get around 50 - 55mpg.
I have found that when driving along roads at 40-45mph you can coast along in EV mode. When you hit 46, it will bring the engine in. That's when the mpg drops rapidly. Economy starts to increase again, up to 70mph. This would explain why you are getting lower mpg than you were expecting.
It takes a little while to learn how to drive the Hybrid efficiently. Patience and a very gentle right foot (this also includes the brake pedal) all help.