HP crossover: the knight bus: found!

[sheffsfic]

Hello: can anyone help me with a story I'm sure I saw rec'd recently please?  It's a Harry Potter verse story, where Sherlock is a wizard who obliviated himself as a child and doesn't remember he has magic.  He discovers it when he and John are attacked (by muggle-baiters, I think?) and he accidentally summons the knight bus.  I believe Mycroft was either the Minister of Magic or the muggle liason with him?  But it's the knight bus and the obliviating that I remember, but I can't track down where I saw it.

Can anyone help, please?

Edit: found in incredibly short time by sail_aweigh: it's Knight Magic by suitesamba