Language Settings - Power BI - Cannot set to British English

When our Office 365 users sign up for Power BI, the Language setting in Power BI seems to automatically set to English.

It appears that once this setting is set, the language for that users Power BI account is locked to US English. You cannot remove this setting once set.

We need british english, but this is not an option in the Language settings drop down box.

We have 1 user who doesn't have this setting defined and the language is taken from the browser settings as we would want. 

Any ideas on how we can clear this setting for our other users/stop is autmoatically setting upon account creation?

Thanks,
Adam