I am aware of AVEN, yes, thanks. As to Holmes and the Doctor ... well, the fandom of the BBC's recent reimagining and that movie with Robert Downey Jr (and the rest, frankly) would probably have real arguments with you about Holmes being asexual because of the heavy Holmes/Watson slash fanbase. But then again, one could argue the same with Spock beyond Pon Farr and people slash him with Kirk all the time. As to the Doctor, while I couldn't really comment about Doctors 1-7, even I'd argue with you about 9 if for no other reason than the euphemistic comments about 'dancing'.

...I think the closest I've ever come to a potential asexual in media is Daria. Huh.