[TYPO3] Why is tt news backend in German

[Another Vision]

Hi List
 
This is driving me mad.
 
I'm developing a typo3 v4 site and I've loaded the tt-news extension. 
 
The front end of the site is showing up fine, in English as I'd expect. But
the back-end interface of tt-news is displaying in German, as it the plug-in
text in the 'New Content Element' page.
 
I've tried adding:
 
config.language = en
config.locale_all = en_EN

to the TS Setup in my main template, but it's not working. Is it because I'm
testing using the Typo3 WAMP 4.0 environment?
 
Any help much appreciated
Mike