Re: [Commons-l] GFDL vs GFDL-en in derivative works

I ran across a typical badly-attributed derivative of Wikimedian images and corrected the page (http://en.wikipedia.org/wiki/Image:UK_Legislatures.png). However, one of the source images is GFDL/cc-by-sa multilicensed and another is GFDL-en licensed only. Is the GFDL compatible with GFDL-en for the purposes of derivative works - and if so should the combined license be GFDL or GFDL-en (preserving those disclaimers)? Unfortunately, the author of the GFDL-en licensed work has gone, but the multi-licensed picture's author is active - so the image could be preserved by getting permission for GFDL-en. That's sub-optimal, but it still beats deleting....