Theres one thing that Harry Potter has that YSM doesnt.. The magic, the quidditch, the wands, the spells, the potions. So no, i dont think so. Yes, there could be similarities, but i wouldn't consider it as plagiarizing the whole character or story. Their stories are told in different ways eventhough it could be in a same setting or same sidekicks. Harry Potter grew with us, as well as the books that JK wrote. I dont recall having a lot of series for Sherlock Holmes though, well correct me if im wrong And harry isn't a detective.. he's just merely a target, always