Going Against the Grain of Potter Cliches

[Disruptor]

Bob is going to run into the main problem with the Harry Potter world that I did.  Doug is Competent.  British wizards are not.  Which should take care of the other big clice of drawing the battle out with Voldemort to Harry's 7th year.

You throw tar around with a large brush, sir. Summarizing the situation as "derp British wizards are incompetent" is in itself one of the more pernicious cliches in Harry Potter fanfic and fandom.
Doug is a highly-trained special operations soldier with (as of DW8) something around a hundred years of combat experience solo and in groups. Almost every witch and wizard we see in HP is... just a bunch of guys, really.
EDIT: On that note, here's a cliche I hope to see get dragged out & stomped on with big heavy hobnailed boots - "Dumbledore's Army" organizing as a real army where the self-taught half-trained teenagers are suddenly supersoldiers capable of taking down Voldemort's goon squad.

Doug is HIGHLY competent and there probably won't be a DA.
As to catergozing the British wizards as incompetent, well with the way JKR killed off the competet characters: Amelia Bones, Mad Eye Moody, Remus Lupin, Tonks, it is hard not to.  Judging by Slughorn's class for 6th year, that was potential people who would be allowed to pursue and auror career or medical.  The potions requirement savaged British competency thanks to Snape's unprofessional conduct. 
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Tom Mathews aka Disruptor