OK, think I've found out what the issue is. I turned wifi/3G back on permanently and my battery has now dropped only 2% in 30 minutes. I guess there is something that is permanently trying to access the network and is sucking up battery when it can't connect.
Not sure what it can be though as I don't have anything setup to automatically update and my mail is set to push.
My phone been on 14hr 35 now and got 30% left been using 3g and gps quite a lot too