Default [Q] Region unlock. downgrade

Hi all,

I have a note 2 N7100 4.3
AP XXUEMK9
CP XXUEMJ9
CSC BTUEMK2

This is unlocked to UK networks. I tried to use the phone while in Africa and Asia, while on holiday and I couldnt. So I tried to downgrade it to 4.1. Triggered knox and almost softbricked. Now back to stock as above.

I have rooted the phone with superroot and the knox has been turned off. Tried Region Lock Away (Chainfire) Didnt work.

Can I now safely downgrade to 4.1? Any experiences?

What if I ODIN an Asian ROM. Will it then take an asian SIM?

Also, has anyone managed to unlock the region lock for the new samsung phones? I was told that I have to use a UK SIM in the phone when I go to Asia and make a 5 min call. Then the region lock should go away. This was from Samsung UK tech support. Has anyone tried this?

Thanks for your time and effort