Two things seem to have sorted my flaky battery life. Firstly, Background App Refresh, check only the apps you want to keep up to date are selected. All of mine were selected for some reason. And secondly, Handoff and Suggested apps. I've switched these 3 options off as I don't need\want any of them.
I've noticed a few minor bugs such as keyboards not appearing when the ought to.
Also if you open the clock app and display world time clocks (analogue) and rotate through 90 degrees you get a line of clocks. Under the line is a series of dots to indicate you can swipe the line of clocks to see the ones that are 'off the edge'. Sometimes the dots and clocks are on top of one another!