It is of course, Four Tet's Late Night Tales mix from 2004 and for a brief time you could download it for free.
And it wasn't some boo-urns bootlegger, but the man himself. Apparently peeved that Late Night Tales are releasing a re-mastered version on vinyl (they've countered that they're doing this with all their old CDs and he was informed in 2012), Four Tet shared a SendSpace link around (which has now been removed).
You can get a taste of the mix below or just buy it or don't buy it, I don't know but I do know it's a stunningly brilliant mix that is my go-to Sunday morning CD and has never been far from my stereo in the nine years I've had it.
Four Tet also posted a SendSpace link to the track he covered for the mix (one of the USPs of Late Night Tales mixes is that they feature the curator doing an exclusive cover version). In this case, he covered Jimi Hendrix's Castles Made Of Sand and it appears to be still available (NB - it's a WAV not a mp3).
