have finally found the perfect one:
http://www.amazon.com/APC-INPA-Universal-Plug-Adapter/dp/B000BJAQVS
This adapter has worked out really well. The little european prongs
are adjustable so it always fits without pushing (and it fits well
enough to not fall out). It does everything I have ever seen and most
importantly in this regard it does the UK style outlets without being
all big and stuff (aka it packs flat).
Awesome little toy. Well worth the cash.