Won't start. Economy mode

I have a Peugeot 307 and it won't start first time.

If I go to my car in the morning Al the electrics work when I put the keys in and turn them. But I turn the key to start it and the lights turn off on the display but nothing happen's.
But the all I have to do is push the car....not even a full bump start then it starts fine! And it will start fine then all day without a problem. But if I leave it more than a few hours it won't start. The only thing it tells me is that it's in economy mode.

I've been searching forums for weeks and I'm fed up now. I hope someone can be a gem and help me