Help Rapid battery drain

[macca81]

Since the last OTA update from telstra to 5.0.1, my batter has been awful! Even hardly using the phone, the battery is going at around 10% an hour minimum, where I used to get 5-6%
Annoying thing is, it seems to be the OS that's draining it?

Just in the time it has taken to post this (2 mins) I have dropped from 15 to 9%...