I've been searching and searching and cannot remember the name of the fic or where to find it but I remember Buffy went down to South America, maybe Brazil, to track down Spike and he was nicknamed el Diablo Rubio. He agrees to help her and they go to England and there is a watcher/warlock named Collin. Also a leprechaun friend of Spike's. Then also something with Stonehenge and spike getting lightning electrocuted.