I never went but I did go out on the London hard house scene a lot at around the same time (it was a lot of fun!). As far as I knew, Sundissential was part of that whole Midlands/Northern England club circuit in the late 90's / early 00's, along with Gatecrasher, Passion, Insomniacz, etc, so it was a bit different from the London scene, as there was more dressing up in ridiculous outfits, neon, fridge magnets, all that kind of shit.
it's a shame gurn.net went down many years ago, I used to enjoy looking at the photo galleries from stuff like Sundissential in bemusement
generally the music was bouncier than in London, and they were really into the donk bass sound (at the time we used to call it 'oink oink' hehe), stuff like this