在Selenium Chrome for Behat测试中将语言设置为en-UK

I am currently trying to run some behat tests using the @javascript tag. I am running a docker environment with Symfony 3.2 and I have attempted to change the language for chrome by setting an argument within the behat.yml:

  chrome:
     switches:
       - "--window-size=1200,800"
       - "--lang=en-UK"

The problem I am trying to fix is the fact that <input type='date' /> is asking for an American format but I need the format to be UK in Selenium Chrome...

Any ideas?