and this advice:
Although strong wind is always an accompanying force along with big waves, it is the increasing swell heights building in the mid Atlantic that are the most important to the photographer. Waves are predicted to be in excess of 30-40ft, but it’s the rogue waves that should be looked out for. Every twelfth or thirteenth wave seems to pack that extra ingredient, so with the right composition some truly spectacular images can be captured.I am wondering how do they arrived at the "every twelfth or thirteenth wave seems to pack that extra ingredient" statement. Anyway it should be a place for big wave aficionados.
I also found this Youtube video of Longships Lighthouse took on the morning of March 10, 2008:
and this one "taken on the 7th of december 2007 in "Raz de Sein" at the western tip of France, in Brittany, on a (very) stormy day"!
More info on the lighthouses can be found here.
Happy wave watching!