I have disabled non-Prestashop modules. Nothing changes.
I have disabled overrides. Nothing changes.
At each of those stages I have deleted the cache files as you suggested earlier. I have closed the browser in question as well. Nothing changes.
I have changed the default language back to English US. I have disabled the en-GB language.
Yet I still get errors in translations to en-GB. Even though it is disabled.
I have also checked the webserver, phpmyadmin is set as English, not English (United Kingdom)