Hello LuizScruz,
I disagree as all my computers were originally setup from scratch with a unformatted space as the destination so I believe the problem also happens with a clean install.
I would not be willing to reinstall Windows again from scratch as I have installed a lot of program and customised my settings and the payback of an inconsequential setting reflecting correctly is just not worth it.
As I see the same problem on 3 of my computers that I have checked (possibly more in the household) I believe it is a bug.
The bug being that the Control Panel/Region/Administrative incorrectly shows English (United Kingdom) as the Display language when the Display Language in the Setting/Language area is set to English (Australia).
I posted this thread merely to highlight a bug in Windows 10 in case Microsoft would fix it (unlikely) but more so to provide a thread that could be found if any other Australian Windows 10 users encounter the same problem and search for an answer. This way they can rule out personal delusion as a cause!
It is not the first bug I have found with Windows 10 and will not be the last.
I have said this before but will say again Windows 10 is the flakiest Windows I have experienced and I have been a Windows user since Windows 3.1!
Regards,
Flavio