Well, I've solved my sleep tracking issues with Sleep++. I can't remember who suggested that but thanks, whoever it was. I like it. I was switching back to a fitbit at night for a while because it was chewing battery (25% overnight) but now its only eating maybe 8%, I can charge up before bed, then not need to charge again until late afternoon.
I've tried some other apps but because you need to fiddle with the phone either before or after or both, they just dont work for me. It would be good if Sleep++ was automatic, but that will come in time, I guess. I just have to remember to tell it I'm going to sleep and then again when I wake..
There is an automatic tracker called sleep watch, but it doesnt always detect sleep, especially if you're restless. You can add later though. Anyway, all in all I am happy with my watch, battery life since the last update is good, and I love its presentation. Now need to flog off the fitbits.