Iphone 6S battery issues

My 6s is a few months old and I have some battery issues. Basically it used to shut off at 5, 6%, no huge big deal, but this has blown out to 12, 13% now it shuts off as high as 35/40%. There's no consistency to it though, it can sometimes last right up to 1% although this is very rare. Occasionally I've managed to restart it and it's lasted another hour and the battery % even increases without charge i.e it shuts off at 30% I managed to get it back on and it climbs to 32%. I've updated to the latest IOS and restored to factory defaults numerous times with no luck. I've taken it into my local Apple approved repair centre (Macworx) and was able to demonstrate the battery issue, but they ran a number of tests including a battery health test which came back as all OK. So I've spoken to Apple who say take it into their store, which is miles away, but I'm guessing they are going to want me to demonstrate the problem, which I can't always do and I'm sure they'll just run the same tests as Macworx. It's still covered under it's 1 year manufacturers warranty. Has anyone else has this issue?

 

I got mine in November 2015

--- Post Merged, Jun 2, 2016 ---

I wouldn't call 30/40% low on power but anyway, the other issue is the battery life is abysmal so going from 100% to 30% takes no time at all. I have to ensure anything remotely power guzzling is turned off, like Bluetooth, but then half the phones functionality is gone.

 

No I'll do that tonight.

--- Post Merged, Jun 2, 2016 ---

The main issue though isn't the battery life, it's the battery indicator which I think is probably a software issue? i.e reporting an incorrect reading. But then it will die at 30% and come up with the "plug it in to charge" symbol, however you can sometimes manage to power it back on for 5mins, then it goes off then you power it back on and it stays on for another hour. The other day I was trying to demonstrate the crap battery, it was on at 11%, turned the brightness way up, put on a video and 30 mins later it was still on 11%! WTF...

--- Post Merged, Jun 2, 2016 ---

Just normal room temp most of the time.

 

So I took it to the Apple store and they very reluctantly replaced it after a good 20mins of arguing with the "genius" appointed to look after me. Unfortunately the new phone is doing exactly the same thing.... does anyone know if Apple do refunds? I do not want a 6s!