li (implied)

I have like a 450 page fan-compiled guide to trip hop history if you want

i can speak a little bit to british electronic music of the era, though i wasn't alive at the time and i'm also not british so grain of salt.

you'll definitely want to read about warp records. here's a writeup from fact magazine, one from dummy, and one specifically about bleep techno from RA.

also here's a particular famous interview with aphex twin specifically.

for documentaries, trash theory did one on aphex twin that's good and might have some information you'll find interesting.

in general i don't think that the british electronic scene had the same kind of underground gold rush as the us alternative scene. a lot of the bands that were signed to majors had never been signed to underground labels, and a lot of the biggest underground artists either never signed to majors (aphex twin) or didn't sign until way later (the prodigy). the popular music at the time in britain sounded very little like the underground music at the time. while in the us major label bands were quick to co-opt the sounds of the grunge and punk underground, britpop bands rejected both american grunge and their own homegrown shoegaze in favor of a sound influenced by british pop music of the 1960s.

I was hoping the Hip-Hop Family Tree series would be a good reference for you but it only goes through the 80s. I’m mentioning it anyway even though it doesn’t answer the question because if you don’t know about it, you should! It’s pretty nifty.