I'm reminded of an anecdote one of my teachers used to tell. She was from Scotland, where the prohibitions, being part of Great Britain, on witchcraft loosened considerably during WWII. It was known that there was a network of spiritualists and witches working against Hitler, and their efforts were secretly applauded.
I have absolutely no proof of this -- these are the stories I heard in the 70's and 80's. Underground stories, if you will. Gerald Gardner might have been one of the ones who wrote about it, but I got rid of his books too.
I've been watching a lot of British drama lately, and very recently I watched a reference to this underground occult movement-to-bring-down-Hitler. It was part and parcel to an unrelated story. But what did the writers do - they attributed the movement to Crowley. I just know that this is inaccurate. It seems as if he's the only idea which survived the blood, sweat, and tears of those actually involved in that Work. On the one hand, a gross injustice of "history" -- on the other, as Michael intimated, the ones involved in the work of the shaman do not take credit, and prefer to work in obscurity, anonymity, eschewing "glory". They aren't famous writers describing their process.
So did Lovecraft have Crowley as a model? I don't know, because there's a lot which is attributed to Crowley which is not accurate. (That, and I don't know Lovecraft's work.)