If I remember correctly (which is a loaded statement at my age), it was Mike P and I think he said this was around 1988ish, and I think was prompted by me asking if Richard really was making stuff as far back as 1985 (which he really was!)
I think Mike P even still has some of these cassettes...
Cool, thanks! If I remember correctly, wasn't he the one who pointed out how Aphex Twin's mystery box in that Aphex Effect interview was fake? So him vouching for the other thing he said in that interview seems to have a bit more weight to it, if he's happy to call out that other bit.
Damn you lot, fuggin' my b'liefs up'n'down'n in'n'out!