Well I updated mine last night. Went to bed with battery at 80%. Switched it on this evening having not used it at all and the battery was at 13%. It used to last for days and days without touching it. On the phone I had a battery drain issue when I upgraded to 4.0.4 but put it down to google+ syncing preventing deep sleep mode. The phone is now sorted. Am just about to start playing with the tablet to see if I can pin down what has caused this dramatic drop in battery life. If others discover the issue before me, please feel free to post in here. It may save us all a bit of time.