Harry Potter and the Key of Dagon

I decided I wanted to do a Buffy/Harry Potter crossover. I enjoy reading them, the two worlds fit well together, but I also wanted to avoid a couple of the things that have bothered me about many of the previous crossovers I've read:

1) No one is anyone's long lost relative.
2) Giles is not a Hogwarts graduate who has been hiding his wand in a drawer for seven years.
3) Draco Malfoy is a nasty little git.

I played a little bit with the Harry Potter timeline, to make Harry's fifth year at Hogwarts take place at the same time as season 7 of Buffy. This story starts during the summer following The Order of the Phoenix and Chosen.