Default language not recognised

OpenCart no longer seems to recognizes the default language setting. Instead of seeing the "translation", all over the site I see different placeholders :

[text-enabled]
[text_home]

And it is causing all sorts of errors throughout the site.

I only have one language under Localization -> Languages

Language Name: English
Code: en-gb
Locale:en
Status: [text-enabled]
Sort Order:1

Under the store settings, the language of the store is set to English.

Does anyone have any suggestions to reset the language setting ?
Thanks in advance.