Did you realise you replied to a post from 2014Al
I have had my Ampera a few weeks, its a second car so not using it much until I can put a cherished number on it so waiting for the V5 to come back, but absolutely love it. Although not answering your question exactly, let me give you my experience with respect to Ampera economy. I went from Solihull less than half charged showing only 15 miles electric range to Coventry and back and combined mpg showed as 101 for the whole journey. In short I'm amazed, but its not all about the economy. Its a really nice experience. As I mentioned on another post, a ICE car raced past, and seemed really outdated. I've got a little sports car that gives me 30mpg if that, but realistically I'm starting to think the Ampera is all I need.
Anyway - Welcome to the "Ampera Future from the Past" and you will find lots of info here. Hopefully you will make the "50 EV mile" club soon