The 'Great War Special Interest Group' (GWSIG) is based in the UK and issues a quarterly online magazine (Newsletter) which has a lot of information, articles, reviews and builds.
The newsletters, which go back to 2014, are free to view or download from the GWSIG web page (see Dave W earlier post with link).
Membership of the GWSIG is also free with members from around the world.
There is also a Facebook page as well:
https://www.facebook.com/GreatWarSIG/Mike