Default UK Official 4.3 Update Issues


I have updated my Note 2 GT-N7100 to UK JB 4.3.
A little background information: tired of waiting for this update, I first flashed the India 4.3 update using odin. I experienced one or two issues, so then I rooted and flashed CM 10.1.3 stable. I was not 100% happy (couple of minor issues with the ROM including low volume). Then UK 4.3 update was released and so I flashed it using Odin.

I am experiencing two annoying issues and would be grateful for some advice please:

First issue:
Almost every time I turn on the device when I reach the home screen a message displays - select SIM service. I have to select either T Mobile/EE, or Virgin. I select the first option as I am with T Mobile. Internet/email etc all works fine.
I have been into Settings - More networks - mobile networks - network operators - and selected "T Mobile". I have also selected "select automatically". The problem still remains whatever setting I choose.

I have contacted T Mobile about this issue, they sent a configuration message to my device to set the APN. I have also contacted Samsung, they did not know how to advise me at all, other than do a factory reset. I did carry out a factory reset in stock recovery after flashing the update.

I don't know whether this helps but I also have a Galaxy Note 8.0. The cellular version with a T Mobile SIM installed. This is running JB 4.2.2. I have no issue with this device. The APN setting is different to that set on my Note 2. Could the APN setting be the issue? I am unable to set the same one as the Note 8.0, it just jumps back to the default "ee" APN. Which I am also unable to delete.

Second issue:
I turned off my Note 2 at 15%. As I usually charge when off, I plugged in the charger. After a few minutes of charging, I clicked the home button to light up the battery meter, the battery meter flicked momentarily - whereas it didn't before the 4.3 update and it indicated it was three quarters charged. Which was obviously incorrect. I then turned off the device from charging and started up the device and charged whilst on, no problem. Does anyone have any thoughts on this issue?

Whilst not major problems, I really like my device to function flawlessly. Should I stay on 4.3, or flash back to 4.1.2?

Thanks in advance.