Hi. Is there an option somewhere for configuring a user’s date format? It seems at present to be hard-wired to the user’s language rather than to their Location.
In UK English 
we use dd/mm/yyyy, but the system forces the US English 
standard of mm/dd/yyyy.
The default english in Java is en-US, therefore dates are coded for US.
The selected language is determined from the list of browser languages and compared with the languages known/allowed in goobi. The first suitable language is used.
You can try to force en-GB explicitly.To do this, the ‘en-GB’ must be added before ‘en’ in faces-config.xml. But this probably also means that the messages_xy.properties must also exist for en-GB.
Thank you, @robert.sehr, that’s done the trick. 
And despite that 
I’m still getting help messages in English.
The only snag I’ve spotted as yet is the absence of appropriate flags, but that’s fixed with:
mv /var/lib/tomcat8/webapps/goobi/uii/template/img/flags/en.gif /var/lib/tomcat8/webapps/goobi/uii/template/img/flags/en_GB.gif
cp /tmp/install/goobi-workflow/Goobi/webapp/uii/template/img/flags/us.gif /var/lib/tomcat8/webapps/goobi/uii/template/img/flags/en.gif
… so that the language selection offers:
