Libre Office will not stop reverting to USA language (even after uninstall)... how to stop it?

I'm in UK, but each time I create a new text document the language always starts as English USA. I've gone into options language settings and changed all to English UK, but every time I create a new document, the language is again English (USA).

I noticed the default language for documents setting always reverts back to USA, no matter how many times I change it and set it as UK.

In attempt to put a stop to it once and for all I removed the USA language pack: sudo apt remove libreoffice-help-en-us and rebooted my PC... but, somehow, Libre Office still defaults and reverts to English USA.

At this point I'm puzzled, can anybody recommend a way to stop this from happening?

I'm on Xubuntu 20.04.2.