Yeah as everyone is saying that sounds about right!
I recently traded in my Fiesta Zetec S 1.6 TDi, i could normally manage around the 50mpg mark, for a 57 Leon FR PD170 and i'm only getting about 39/40 mpg out of it. I have found if you take it easy on A roads, 50-60 you should be able to get it up into the 50's but any faster and you will struggle.
Also, if you're aiming for best fuel consumption, don't use Cruise Control, it's a lot more aggressive with the accelerator than your foot can be.
One other strange thing i did find since driving it was that i always expected a 6 Speed gearbox to give you a good cruising gear to bump up your mpg over motorway driving but at times i find it more economical to leave it in 5th! Not sure on your experiences but i've only had it for a month or so now so just getting to grips with it.
Your best bet, or what i do anyway, is having the heads up display showing the 'live' mpg figures and match your foot position and gear choices to mpg and you'll soon find you can adapt your driving style to get the most out of it. But be warned, booting it out of roundabouts is a sure fire way to make them figures go down!