I produced a slide showing what i understand (or, perhaps in some cases, misunderstand) to be the groups in the UK and Europe with a remit that covers OA. This is not comprehensive, I’m sure. Because i created it for Jisc purposes, it has a Jisc flavour to it. However, it might be useful for others perhaps, to understand the landscape. Here it is, as a MS Powerpoint slide:
scholarly communications groups
And as a PDF:
scholarly communications groups
Any suggested improvements, please let me know (neil.jacobs@jisc.ac.uk or use comments below). If there are a few suggestions, then I might put a revised version up here.