I've been using Zorin from a bootable USB stick for quite a long time - and it all worked fine until a couple of weeks ago when various settings became 'fixed' somehow - i.e. I couldn't change the screen background any more or the screensaver timeout etc. In the end, I zapped Zorin and re-installed it onto my USB stick.
I'm still using last year's version (Zorin 15) but everything's back to normal now - except for my keyboard layout. I've set my region and language settings to English and United Kingdom and I looked under Devices->Keyboard but that only seems to offer settings for various keyboard shortcuts.
How/where do I set my actual keyboard layout to UK layout?
I use a UK keyboard as well. First thing though, you have the UK keyboard in the 3rd position, it will default to whatever is in first position.
But yes, delete all the rest, and only keep the UK keyboard. I had an issue in the beginning as well, and it seems to be a Ubuntu problem since other distro's based on Ubuntu all had the same problem of the keyboard defaulting to U.S. I went in and changed some of the configurations files, (sorry, I don't remember which ones) and I've not had a problem since.
Please mark DeanG's response as solution. Have marked your issue as [SOLVED].
You will ironically find English US as the default language on most Operating Systems. In that other OS if you remove US language it sometimes Bork's updates!