This is a common issue with the Chrome Browser. Most other browsers use the system date and time settings, but Chrome needs to be set up individually.
- Go into the google Chrome settings by clicking the 3 dots in the top right corner of the screen or by navigating to chrome://settings/
- Scroll down to the language settings (or search language in the search box)
- First make sure you have 'Display google chrome in this language' checked for the English UK option.
The next stage is a glitch with Chrome itself. It will only apply the change when actually remove the USA as a language from the Languages settings by clicking on the dots beside it and selecting 'remove'.
When you restart chrome the language and date formats should all be set to the UK standard. You can add in English US again afterwards if you need to.
Hope this works, but if you have any problems we can work through them together.