The piece is called "Dr. John Dee, the Necronomicon & the Cleansing of the World", and was written by Colin Low in 1996-2000. It's basically an extended riff on H.P.Lovecraft, John Dee, the Voynich Manuscript, Aleister Crowley and the Necronomicon, and how much they do (or don't) relate to each other.
The problem with Lovecraft fans is that they often enjoy emulating what their gloomy hero liked to do: mix fantasy with history until they both blur together into one great big glob of either historicised fiction or fictionalised history (whichever you prefer, it doesn't matter much).
And so it was that in 1978, a book called "Necronomicon" appeared edited by George Hay (reprinted in 1995), containing a claim by David Langford and Robert Turner that Lovecraft's fabled Necronomicon was not only real but "had been preserved by Alkindi in his treatise The Book of the Essence of the Soul", parts of which had in turn been enciphered by John Dee in his Liber Loagaeth. With an introduction by Colin Wilson, it looked convincingly like real historical research... but (as you've probably guessed by now) it was merely faux Lovecraftian nonsense.
Colin Low's article then goes on to collect together various strands apparently connecting Dee (via Enochian and Choronzon) to Crowley and his well-documented adventures with demon summoning. It's all entertaining stuff, but the possible presence at the ball of a Lovecraftian mischief-making poltergeist tends to rather reduce its reliability for the reader. So in the end, does Low's account amount to something special or to something of nothing? Basically, I think you'll have to make your own call.
However, I do find Low's summing-up of the Necronomicon fiercely attuned to much that has been said about the Voynich Manuscript: "The Necronomicon is a hollow vessel - it booms resoundingly, but has nothing in it but the projections of our own fantasies." Which is a shame.